Materials & Metallurgy - November 29, 2001
Official Transcript of Proceedings
NUCLEAR REGULATORY COMMISSION
Title: Advisory Committee on Reactor Safeguards
Materials and Metallurgy Subcommittee
Docket Number: (not applicable)
Location: Rockville, Maryland
Date: Thursday, November 29, 2001
Work Order No.: NRC-117 Pages 1-135
NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers
1323 Rhode Island Avenue, N.W.
Washington, D.C. 20005
(202) 234-4433
UNITED STATES OF AMERICA
NUCLEAR REGULATORY COMMISSION
+ + + + +
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS
(ACRS)
MATERIALS AND METALLURGY SUBCOMMITTEE
+ + + + +
THURSDAY
NOVEMBER 29, 2001
+ + + + +
ROCKVILLE, MARYLAND
+ + + + +
The Subcommittee met at the Nuclear
Regulatory Commission, Two White Flint North, Room
T2B1, 11545 Rockville Pike, at 8:30 a.m., F. Peter
Ford, Chairman, presiding.
COMMITTEE MEMBERS:
F. PETER FORD Chairman
MARIO V. BONACA Member
THOMAS S. KRESS Member
WILLIAM J. SHACK Member
ACRS STAFF PRESENT:
Noel F. Dudley
ALSO PRESENT:
Maitri Banerjee
Mohamad Behravesh
Helen Cothron
Robert Cullen
Farouk Eltawila
Bob Exner
Lane Hay
Gary Henry
Robert K. Johnson
Ken Karwoski
Bob Keating
Herm Legally
Steve Long
Louis Lund
Mati Merilo
Rick Mullins
Emmett Murphy
Jim Riley
Edmund Sullivan
I N D E X
AGENDA ITEM PAGE
Opening Remarks by Chairman Ford . . . . . . . . . 4
Introductory Remarks, E. Sullivan. . . . . . . . . 6
NEI Presentation, J. Riley, NEI. . . . . . . . . .15
NEI 97-06
NEI Generic Change Package (GCP)
Present Issues
Concerns with GCP and NEI 97-06. . . . . . . . . .46
E. Murphy, NRR
Staff Presentation (Cont.), E. Murphy, NRR . . . .93
Proposed resolutions
Status and Plans
Standards Issues, EPRI, Mohamad Behravesh. . . 100
NEI Status, J. Riley, NEI. . . . . . . . . . . . 114
Discussion, Chairman Ford. . . . . . . . . . . . 121
Adjournment, Chairman Ford . . . . . . . . . . . 135
P-R-O-C-E-E-D-I-N-G-S
(8:36 a.m.)
CHAIRMAN FORD: The meeting will now come
to order. This is a meeting of the ACRS Subcommittee
on Materials and Metallurgy. I am Peter Ford,
Chairman of the Materials and Metallurgy Subcommittee.
The other ACRS members and consultant in attendance
are: Mario Bonaca; Thomas Kress, and William Shack.
The purpose of this meeting is for the
Subcommittee to review the latest revision of the
Nuclear Energy Institutes (NEI) 97-06, "Steam
Generator Program Guidelines," and the Generic License
Change Package. The Subcommittee will gather
information, analyze relevant issues and facts, and
formulate proposed positions and actions, as
appropriate, for deliberation by the full Committee.
Mr. Noel Dudley is the Cognizant ACRS
Staff Engineer for this meeting. The rules for
participation in today's meeting have been announced
as part of the notice of this meeting previously
published in the Federal Register on November 9, 2001.
A transcript of this meeting is being
kept, and will be made available as stated in the
Federal Register Notice. It is requested that
speakers first identify themselves and speak with
sufficient clarity and volume so that they can be
readily heard. We have received no written comments
or requests for time to make oral statements from
members of the public.
Since the early 1990s, the staff and the
industry have worked to develop a mutually agreeable
regulatory framework to ensure steam generator tube
integrity. In 1998, affected licensees committed to
NEI to follow NEI 97-06, "Steam Generator Program
Guidelines," and the associated Electric Power
Research Institute (EPRI) implementing programs.
It was January 2001 that NEI revised NEI-
97-06 and the implementing programs, and has developed
an Industry Steam Generator Program Generic License
Change Package, which provides templates for licensees
to amend their technical specifications. It is our
understanding -- It is the ACRS' understanding that
the staff and NEI are in general agreement concerning
the intent of the NEI 97-06, Rev. 1, and the change
package.
The last time the ACRS was involved in
this specific issue was in early 1999. Since these
discussions are approaching agreement, we thought it
appropriate to have a Materials Subcommittee meeting
to bring us up to date so that there is no delay on
our end when this matter is brought up to the full
ACRS meeting next week on December 6th.
We will now proceed with the meeting, and
we will call upon Mr. Ted Sullivan of the Office of
Nuclear Reactor Regulations to begin.
MR. SULLIVAN: Thank you for that
introduction. I would comment that a lot of the
things I was going to say were contained in your
introduction. So I'll skip them and possibly hit some
other points.
My name is Ted Sullivan, and I am just
going to make a few introductory remarks maybe to st
the stage for what is to follow.
We met with the Subcommittee, I think, on
September 26. The purpose of that briefing was to go
through the steam generator action plan as it
currently exists. We covered a number of topics,
basically falling in three broad categories,
categories of licensing process, NEI 97-06 and the
DPO. That's sort of a breakdown of it.
We devoted a fair amount of time to the
subject of NEI 97-06 and the NRC's process and status
for revising the regulatory framework for steam
generators. Our understanding was that we should come
back and provide more detail, and we thought that this
was a very good request, because as Dr. Ford said, if
there are comments that are going to come from ACRS,
we would like to get them early and factor them in.
Basically, the rationale for why we are
doing this, this being revising the regulatory
framework, is that our existing requirements are
prescriptive. They are out of date, and they are
really not focused on the right thing. They are
focused on surveillance.
The textbook is on surveillance and repair
criteria. They are not focused on the condition of
the tubing while the plant is operating or what we
refer to as tube integrity.
We have been at this for quite some time,
revising the regulatory framework. We worked on
rulemaking in the early to mid-Nineties, and we came
over, I think, a couple of times to brief ACRS on the
rulemaking effort.
That was superseded, for reasons that we
explained back then, with a generic letter and
regulatory guide approach. That kind of got off the
ground. We made a fair amount of progress in terms of
getting a generic letter drafted. We got the reg
guide out for public comment.
In a fairly similar time frame, the
industry started working on kind of a similar program
which has been named NEI 97-06. It is an industry
initiative. They asked us to put the generic letter
on hold and consider that as an alternative approach,
which we did.
We received -- We spent a lot of time
discussing the program and how it would fit into the
framework and what a generic license change package
would consist of. Eventually, after a lot of
discussion, NEI was able to send in a package, which
is on my next Vu-graph, in February 2000.
Shortly thereafter, the Indian Point 2
failure occurred, and we were basically sidetracked
for a year. We got the review going in January of
this year, and as I have previously noted, the review
of NEI 97-06 is part of the steam generator action
plan.
Through a number of interactions that we
have had with industry, including the workshop we had
earlier this year and some review that we have
explicitly done on the guidelines that are part of the
NEI 97-06 program, we generated some concerns that we
are working on and that, I think, will constitute a
lot of the discussions that are going to follow.
The upshot of what we've done is we
basically altered our strategy for how we want to
proceed into basically kind of two time frames, a more
near term approach to get us over these concerns, and
a more long term approach to get us back on track with
a fully performance based approach.
I am going to be deliberately vague,
because I think that is going to be explained a lot
more in detail later.
Now the presentations to follow: Jim
Riley and, I think, one of his other colleagues is
going to talk about the NEI 97-06 industry initiative.
This is an initiative that is in place in the nuclear
utilities in this country, and we thought that that
would be a good way to set the stage for how our
regulatory framework is going to try to build on top
of that.
So we thought it would make sense for NEI
to make a presentation first, and someone from the
staff will follow. We are not exactly sure who at
this moment, but we do have Vu-graphs and a couple of
people ready, willing and able to fill in, if Emmett
isn't here.
MR. LUND: Emmett is running late.
MR. SULLIVAN: Okay.
CHAIRMAN FORD: As you are already up
there, maybe you can give us some idea. It's
disturbing that this has been going on for nigh onto
ten years in one form of the other.
MR. SULLIVAN: Yes.
CHAIRMAN FORD: So can you give us some
idea as to when this thing might come to an agreed
upon package?
MR. SULLIVAN: I'll try. That's a good
lead-in for something that I did want to mention.
Because of the Commission meeting that is
coming up on this coming Monday, the staff wanted to
be able to answer that question as best we could. So
our senior managers requested a meeting with NEI,
which occurred yesterday.
Basically, the two kind of near term
issues that we have been working on -- One is to
establish maximum inspection intervals in lieu of
going directly to a performance based approach, and
establishing appropriate regulatory controls on those
intervals within the two issues that we have been
discussing most recently.
We have reached agreement on the
regulatory controls aspect, and we have reached
agreement on the overall concept of the near term
approach and the longer term approach.
The industry is interested in putting in
place a program that satisfies some of their
objectives and not just make this all one way to
satisfy NRC's objectives. Their objectives are to get
longer inspection intervals for plants, where that can
be justified.
They are in the process of resolving a
number of comments that they have generated internally
and that NRC has made on some of the more recent
proposals. They are estimating, based on yesterday's
meeting -- and I'm probably getting ahead, and Jim
Riley would probably address this. But they are
estimating being able to come to complete resolution
on that, including addressing NRC's comments, by the
middle of 2002.
We have basically already started writing
a safety evaluation, and I think we can virtually
have the safety evaluation done by that time frame.
That's our intent.
So that by the end of 2002, we can have
gone through all the rest of the steps needed, which
include such things as putting the safety evaluation
out for public comment, meeting with the Commission
once we have resolved the public comments, and putting
the safety evaluation out in final form in a
regulatory issue summary, which is a vehicle that NRC
is using these days for this kind of activity.
Then what would follow from that generic
activity would be individual submissions by plants of
tech spec revisions. So I hope that answers your
question.
CHAIRMAN FORD: So by mid-2002 --
MR. SULLIVAN: We should have all the
technical issues resolved.
CHAIRMAN FORD: -- Generic Change Package
will be signed and sealed.
MR. SULLIVAN: And delivered to us.
CHAIRMAN FORD: That opens up the pathway
for individual plants to come and make their
individual cases because of the change in the tech
specs?
MR. SULLIVAN: That opens the pathway, but
we have to go through some kind of mandatory steps.
We have to finish our safety evaluation, which we
think will largely be finished by that time, because
we are not going to be operating in a vacuum from each
other.
We have to issue that safety evaluation
for public comment. We may have to come back and
brief you one more time. We have to go to CRGR. We
have to resolve the public comments. We have to brief
the Commission, and then we can issue it in final
form. All of that may take an additional four to six
months.
CHAIRMAN FORD: By the end of the year of
2002?
MR. SULLIVAN: Yes.
CHAIRMAN FORD: So as far as the ACRS is
concerned and as far as committee is concerned, all
you are looking from us today is to say, yeah, you've
got the right technical issue. You are arguing and
discussing the various technical issues. Do we see
any further issues?
MR. SULLIVAN: Right. Are we on the right
path?
CHAIRMAN FORD: And then just go forward
on that.
MR. SULLIVAN: I think that would be the
kind of feedback we would like from the full
Committee.
CHAIRMAN FORD: Jolly good.
MR. SHACK: Ted, just a question. Somehow
in all this, I don't see any mention of severe
accidents. Have those been resolved in some way or
have they just sort of disappeared?
MR. SULLIVAN: Steve might be able to
elaborate, but I think what I would try to say is that
what we are trying to do is put in an approach that
will require -- and not try; we are going to put into
effect an approach that will require licensees to
continue to have NRC approval on any alternate repair
criteria that may affect risk.
MR. SHACK: You deal with it when you are
dealing with the alternate repair criteria.
MR. SULLIVAN: Right. Do you want to
elaborate, Steve?
MR. LONG This is Steve Long with the NRC
staff. Basically, what Ted said -- You will see this
later on when we describe the performance criteria and
how we intend to control the performance criteria
through the tech spec -- this is not really my part,
but the tech spec requirement for a steam generator
program and content of that program being performance
criteria.
So that the performance criteria would
need approval from the NRC to change, even though they
are not in the tech specs directly. Those performance
criteria are things that have come from our design
basis regulation so far that we feel are necessary to
control risk, including the risk from severe
accidents.
We have had some discussions with the ACRS
before about how that's not a very direct control.
Also, we are not sure exactly what we need to control
to, and there's a lot of work that we have also
described to you about the steam generator research
program, part of which stems from the DPO that you all
reviewed and reported on.
As we get research findings that allow us
to know how to allow -- for instance, how much leakage
you can allow in different parts of the RCS and still
be okay during a severe accident, we will be able to
relax some of these performance criteria. But the
intent right now is to be able to maintain control of
the performance criteria that we think are needed to
address severe accidents, insofar as we have them
already at least.
MR. SULLIVAN: Okay. I think, if there
are no more questions, it would be appropriate to turn
the microphone over to Jim Riley.
MR. RILEY: Good morning. Jim Riley from
the Nuclear Energy Institute.
I came with a prepared presentation, but
I, like Ted, found that a lot of the items that you
talked about on your summary were things I was going
to talk about. So I am perfectly willing to focus
this on whatever areas you feel are most beneficial to
you. But here is what I was prepared to talk about.
One of the things I do want to get across
to everybody is the extent of the steam generator
organization within the industry and the degree of
commitment that the various utilities, all the
utilities, have to the steam generator -- their steam
generator programs and the steam generator
organization. I think that's an important message.
I was going to go through kind of a
history of the regulatory approach. I'm not sure that
is necessary, but stop me, move me around on this as
you wish. I want to give you a little bit of a
background on NEI 97-06. I want to make sure
everybody understands what that document is all about,
what it consists of, and what the industry's
commitment to it is.
I'll talk a little about how the program
is continuing to evolve. I do want to talk about the
generic license change package, what's gone on in that
area, and then what we have been doing with the NRC.
As Ted indicated, there is another person
here that will be sharing this time with me, although
the way that we would like to do it is to split up our
time so that I'll let Emmett have his say next, and
then Mohamad Behravesh is going to be talking about
the EPRI guideline that governs steam generator
inspection intervals, because that is clearly the
technical issue that is catching the most attention
right now.
I think it would make more sense to you
and from a presentation perspective if Emmett first
got into his discussion of what are the issues, and
then we were able to present what we have done in the
way of this guideline in a way that kind of answers
the questions that he raises when he does his
presentation.
So that's the way I'd like to do this,
unless there is any objection.
CHAIRMAN FORD: Don't feel shy about doing
this, because I personally am new to this, and I would
love to hear what the background is.
MR. RILEY: Great, okay. I'll be happy to
then. If I get a little long-winded here --
CHAIRMAN FORD: Well, the others will shut
yo up.
MR. RILEY: All right. Let me tell you --
This is a little bit of a history lesson, and we are
going to skip over these first slides to some degree,
but I want to go over this.
The industry has had a Steam Generator
Management Program in place a long time. This thing
was kicked off in 1976 to take a look at corrosion
that was going on, and an organization that basically
involves all the PWRs in the United States was set up
at that time to look at corrosion concerns and see
what can be done about them.
NUMARC entered the fray somewhere along
the line, and since about 1993 has been working with
the Steam Generator Management Project, which is SGMP,
to establish a framework for steam generator
degradation specific management and alternate repair
criteria.
NEI, who evolved from NUMARC, entered the
picture in about 1995, and at that time we established
what we call a Steam Generator Working Group and a
number of steam generator task forces, and I will tell
you a little bit about what the differences are there,
to address different issues.
So industry's commitment to this and
involvement has been extensive and has been
longstanding.
The next -- Approximately the next ten
slides, I'm going to try and summarize, because I
think I'm a little bit short on time, but I'll take
more time if you want on any part of it.
This first slide is a rough organization
chart, I guess you could say, of how the industry is
configured to address steam generator issues. There's
really three arms here.
One is NEI, and I think everybody is aware
of the fact that NEI is the regulatory interface on
the industry issues. In the case of steam generators,
as I mentioned on the previous slide, we have been
involved for about the last six years or more as NEI,
and before that as NUMARC.
EPRI has the technical end of this thing.
EPRI has responsibility for the Steam Generator
Management Project and its organizations and the EPRI
guidelines that provide the detailed guidance on how
NEI 97-06 is going to be implemented.
Then finally, we have INPO's involvement
also through a series of steam generator review visits
that they conduct, have been conducting for a number
of years. In fact, I believe now they have visited
all the plants, and they are now starting on their
second go-round. That's accomplished by peer as well
as INPO involvement where they go in and look at the
industries -- at individual utility steam generator
programs and make some evaluations on how well that
program is being conducted.
So there's three aspects of this. Let's
talk for a minute about how NEI is set up. NEI's
Nuclear Generation Division has a number of working
groups and task forces within it or associated with
it. As you are probably aware, these working groups
and task forces are all set up with an NEI
coordinator, in my case for steam generators, and
participation by the industry on the groups to form
the real core of the membership.
The way the structure is set up with NEI -- and
it isn't even shown on this one, but within the
advisory committees that consist of utility people
within NEI -- it's called the NSIAC. NSIAC stands for
Nuclear Strategic Issues Advisory Committee, and it is
made up of the chief nuclear officers of all the
utilities, nuclear utilities, in the country.
They provide kind of strategic direction.
Underneath NSIAC we have a series of working groups on
various issues that raise to this level of importance
within the industry. One of them is a Steam Generator
Working Group. It's been around for quite a few
years.
Basically, that group is made up of
executives, managers, highly experienced people from
within the industry who have overall cognizance of
what is taking place in the area of steam generators,
kind of policy, what are we going to do about this
one, and they set the task forces to work to actually
do the job of pulling together whatever effort is
required.
The Steam Generator Task Force, a number
of whose members are here today, was set up to look at
this generic license change package, this regulatory
framework, and we have addressed not only that, but we
have also been addressing a series of technical issues
that have come around related to the steam generator
generic license change package over the last couple of
years.
So in addition to that, which is the
structure that basically puts this GLCP in process, we
also have a review board set up under NEI. The whole
purpose of that review board -- and its membership is
also pulled from the steam generator organization
industry -- is to answer questions that come up on
these various guideline documents that are out there.
It has a pool of experts that addresses
these issues, and then puts an interpretation out
which gets posted on the NEI website, so that the
utilities are aware of what is going on and any
particular question that comes up.
That's the NEI organization. The EPRI
organization is -- The SGMP is a pretty large group of
individuals. The SGMP itself is run by a management
-- SGMP management and senior representatives that
look over the SGMP from the standpoint of budget
control, policy, what issues they are going to be
working on, etcetera.
Again, the PMMP is a group of fairly
highly placed individuals. Jack Woodward, you
probably know, of Southern Company, a lot of other
vice presidents, etcetera. Again, the intent is let's
keep an eye on how this whole thing is going, where it
is going.
Underneath them they have senior
representatives, some overlap there between
membership, and again the same kind of a management
function for steam generators, in particular. The
PMMP, as you note, looks over both the management --
the materials review project, the liability project --
I may get that wrong -- the liability which has vessel
head penetration, cracking and other issues on that
side, as well as the SGMP. The senior reps are pretty
much concentrated on the SGMP.
Within the steam generator end of it, the
major organization is called TAG. It's a Technical
Advisory Group. All of the nuclear utilities who are
members of EPRI are members of this TAG organization.
There are meetings, about three meetings
each year of this TAG organization, and typically 80,
90 people, something like that at one of these
meetings, representatives from all these utilities.
They get together for two or three days and share
experiences, and listen to presentations by various
people, myself included, on what happens to be going
on within the steam generator world.
The whole idea of that TAG is experience
sharing, technology development for those kinds of
issues that relate to steam generator corrosion
control, steam generator inspections, and things like
that.
So this is an extremely good mechanism for
addressing technical issues and for hearing experience
from each other that they can use in their own steam
generator programs to keep themselves as much up to
speed on what's going on as possible.
This Technical Advisory Group has a series
of committees set up within it. The committee with
kind of overall responsibility for integrating what is
going on is called the IIG. They have three technical
committees under them that look at the different
aspects of what the steam generator programs are all
about.
One of these is the NDE IRG. They are
responsible for NDE issues, technique qualification,
personnel qualification, inspection intervals which is
one of the things we are going to be talking about
this afternoon.
They've got a guideline that they have
written specifically to address these issues. It's
called the Steam Generator Examination Guideline.
That's been the center of some of this controversy
and, as I mentioned, Mohamad Behravesh is going to be
talking about that to some degree later.
The E & R IRG, as its name implies, does
engineering and regulatory issues. They have three
guidelines underneath them, the in situ pressure test
guidelines which gives us guidance on how to do
pressure testing of tubes, integrity assessment
guidelines which takes the information from the NDE
guys and evaluates it like what's the condition of the
steam generator right now, condition monitoring, what
is it going to be like in order for us to make sure we
can meet the performance criteria at the next
inspection operational assessment. All those things
are in the integrity assessment guidelines.
Then finally, and the last one is going to
skip my mind here -- Help me here. What's the third
one? Why am I missing one? Integrity assessment, in
situ -- Okay, there are only two. The other is in
TSS. Thank you.
Then the third committee is the Technical
Support Subcommittee, and they do long term research
and various R&D type efforts. They have three
guidelines under them: The primary secondary leak
guideline which talks about what action levels we have
at various levels of primary secondary leakage, and
primary chemistry and secondary chemistry which talk
about chemistry controls.
So this organization is basically
responsible for putting together the detailed guidance
of how you run a steam generator program and doing the
work that is necessary to track down the various
technical issues that bubble up from time to time.
They are assigned to one of these committees who are
given responsibility to put something together to
address this thing, come up with an industry position
on them.
It's a very active organization. Not only
do they meet three times a year, not only do they
produce these guidelines which, by the way, are looked
at for revision about every other year and, I think,
pretty much have been revised about every other year.
They only put out interim guidance, if necessary, on
various issues that come up.
Specifically, about a year or so ago, they
issued two -- Well, one was an interim guidance on in
situ pressure testing that came out of the
pressurization ramp rate issue that was a result of
the ANO situation about a year or two ago. The other
one was a general lessons learned from IP-2 and ANO.
That group has continued to be involved in
this pressurization ramp rate study we took which came
out of ANO. We did more work on it, made some
evaluation, tried to decide what this really meant:
WAs there a ramp rate? What was it due to? All that
was falling under the STMP.
CHAIRMAN FORD: Jim, quick question.
MR. RILEY: Yes?
CHAIRMAN FORD: Was there a peer review on
these EPRI documents, guideline documents?
MR. RILEY: The way that these guideline
documents are revised is an ad hoc committee is
selected from within the TAG who are given the
responsibility of developing the revision. Then the
revised document is reviewed by the entire TAG.
CHAIRMAN FORD: Not outside people?
MR. RILEY: Beg pardon?
CHAIRMAN FORD: Not outside people?
MR. RILEY: I believe there is some amount
of outside involvement in that, too. For example, on
the Rev 6, which we are going to be talking about, the
NRC has had a chance to look at that. The vendors
have had a chance to look at it. The NSSS
organizations have had a chance to look at it. So
it's given a wide review.
CHAIRMAN FORD: I'm thinking more of
uninterested parties.
MR. RILEY: Well, no, I don't believe
uninterested parties are involved.
CHAIRMAN FORD: Yes, you're right.
MR. RILEY: No. Then it's approved
through the structure here. The senior reps, the IIG
itself signs off on these documents before they go out
and are used by the industry.
MR. SHACK: Jim, while we are on this, we
seem to be focusing on the inspection issues here and
the frequency. There were some other issues that the
staff had beyond the leak rate when you did the
condition monitoring, just how the tubes were selected
for the condition monitoring.
Has all that been resolved?
MR. RILEY: No, it hasn't been resolved,
but it is being addressed. I can talk about that, if
you would like. In fact, I was kind of thinking we
might get into some of this. So I made some extra
presentation.
I think what you might be referring to is
the steam generator action plan. Are you? There were
a bunch of issues that were identified by the steam
generator action plan and, as luck would have it, I've
got some stuff you guys can take a look at, and I can
talk about this for a minute.
As you know, about a year ago or so, the
NRC issued their Steam Generator Action Plan. That
was kind of a consolidation of various lessons learned
and other things that came out of the IP-2 event.
I think, if I was to categorize the issues
that came out, we could lump them into these kind of
areas: Assessment of degradation mechanisms -- what
do you do about new degradation mechanisms, how do you
assess them, what kind of process do you have to have
in place to assessment? What about hour glass, and
what do you do about those? What are the implications
of all these things?
CHAIRMAN FORD: Before you go, just to
make sure we've got our definitions right, to me,
steam generator action plan refers to the NRC. Is it
the same thing we are talking about?
MR. RILEY: That is the same thing we are
talking about. A whole number of items were
identified. Twenty-seven of them were shown as things
that the industry was supposed to be doing something
about.
You take those 27, and you kind of pigeon-
hole them. These are the pigeon holes we came up
with, and this is nothing new to Ted, of course.
We've been working with Ted and with Emmett and Louise
and others on this. In fact, I think this was
Emmett's characterization of how these things would be
pulled together into bins, if you want to call it
that.
Anyway, NDE data quality, NDE
qualification, NDE data analysis for all issues that
were identified as part of the Steam Generator Action
Plan. All of those are being addressed as part of
this Rev 6 work on the steam generator exam
guidelines.
We are talking about inspection intervals.
That's kind of what we are focusing on today, but all
these other things are also being looked at on Rev 6,
and Rev 6 has a lot of new information on these other
aspects. Hopefully, a lot of this is going to be
cleared up when we get Rev 6 finally issued.
Pressure testing: There were some
questions that came out of the action plan on what do
you do about cases where you've got leakage that
exceeds the test equipment? How do you go about
performing some kind of an analysis to decide whether
you had a burst or whether you didn't have a burst,
and how do you establish the criteria, and all that.
That's all being looked at by an in situ
test ad hoc committee. I mentioned earlier, these
committees are set up to revise these guidelines on a
biennial basis. That guideline is up for revision,
and that committee has already been formed, and it is
looking at those particular issues and, hopefully,
will be addressing them and, hopefully, resolving them
as part of the upcoming revision to the in situ
pressure test guidelines.
Operational assessment: That gets right
into inspection intervals, of course, and there's
other questions that were involved in the Steam
Generator Action Plan for operational assessment. We
have an Integrity Assessment ad hoc Committee, and
this one is a little bit different. Even though its
name might imply that they are looking at a revision
to the integrity assessment guidelines, their scope is
a little bit broader than that.
What they were trying to do is get the NDE
community together and the integrity assessment
community together and come up with better tools for
making those two communities talk to each other and
come up with better results for steam generator
inspections, better operational assessments, etcetera.
That committee is also ongoing right now,
and is addressing the operational assessment issues as
part of what they are looking at.
Then finally, the other bins that we've
talked about here, tech specs and NEI 97-06 initiative
implementation, feedback NRC, that's all being handled
as part of the Generic License Change Package
basically by the Steam Generator Task Force, the
people that you are seeing in this room.
MR. SHACK: I get confused gain about
where NRC reviews, what tier documents, what changes.
Suppose in your operational assessment you wanted to
change the probability of detection. Is that an NRC
reviewable change?
MR. RILEY: No, except for the fact that
the NRC takes a look at your operational assessments
as they see fit based on their inspections of your --
their review of your steam generator inspections.
PODs, etcetera, I believe, come off the ETSS sheets,
do they not, which -- and those sheets, the equipment
-- I'm going to fail on the name. But basically, they
are the sheets that define the capabilities of the
different NDE techniques, and they are controlled by
a QA program within EPRI and the NDE Center that talks
about what are the critical parameters of this
particular NDE technique that you want to use and the
kind of performance you can expect out of them. All
that kind of rolls up into a POD.
Now the issue of POD, though, is a good
one, and the industry is also struggling with what do
we do about POD, how do we make it better. That's
part of the Integrity Assessment ad hoc Committee
that's meeting right now, too.
If you want some details on it, we can
probably give it to you, because we got the right
people in this room to talk about it. But in general,
that's --
MR. SHACK: I was more interested this
time as to whether that was within your bailiwick to
change or they had to review that.
MR. RILEY: That's our bailiwick.
Okay, regarding the Action Plan issues,
back to these bins, if you will, I mentioned that
there were 27 industry issues that were identified.
We have written up an initial response on all 27 of
those and provided them to the staff. That was done
the early part of the summer.
We have gotten comments back on a number
of them, not quite all of them, and we are addressing
revisions to them right now. The revisions to these
are tied up -- When I say tied up, I don't mean to use
it from the sense of being stopped, but they are
wrapped up with the work that is ongoing on cycle
lengths, the work that are ongoing with these various
ad hoc committees.
We have reached resolution on, I think,
about three or four of them. The others are active.
They are ongoing, but they are not resolved yet. So
it's part of the continuing effort.
One thing you need to keep in mind with
all of this is we are talking about having a target in
mind for completion of the Generic License Change
Package, but it doesn't mean industry is going to quit
working with the NRC at the time the GLCP is done.
The industry has a commitment to continue
working with the NRC on technical issues as they
arise. Some of these have already been identified.
We are already working on them, and we are going to
resolve them. They may not get resolved at the same
time the GLCP is done, but they will continue to be
worked on.
The Steam Generator Task Force isn't going
anywhere. It will still be around. It will still
work with the staff, and will continue to address new
issues as they come up. These are the ones that we
have in place right now.
CHAIRMAN FORD: So coming from, for
instance, the work that is being done at Argonne or
the work that is being done in the various tasks, one,
two and three, in the action plan within the
NRR/Research, they will just -- There will be a living
document. These guidelines will be living documents.
They will change?
MR. RILEY: Definitely living documents,
and they will change as time goes on and new
information is identified. The SGMP has got the
responsibility for keeping those things up to date,
and like I said, they look at them every other year.
So I'd like to skip through, because I
really talked about most of these slides up to Slide
14, which provides a summary of what I've said. But
I guess this is the message I want to leave you with
here with respect to the industry steam generator
organizations.
It is a highly active, running all the
time organization, and does address issues promptly.
The SGMP, as a matter of fact, had people at TMI
helping with TMI's evaluation of what went on with
their tube sever issue.
We've got a TAG meeting that is coming up
in a couple of weeks. We intend to have
presentations. We will have presentations from TMI,
what went on there, just for an example. That's
pretty recent stuff, and we've already got people
involved with it.
At this TAG meeting we are going to be
sitting down with the folks who are doing the Rev 6
work. We are going to be talking about what are all
these comments we've gotten from the industry and the
NRC. They have been dispositioned to some point. We
are going to talk more about what the final
disposition of these is.
It's a vibrant organization. We have
broad utility participation in this organization from
across the country and EPRI, in general and in the
SMP.
We make a particular effort to encompass
all the different steam generator designs within these
different organizations. The IIG, for example, they
make a real effort to make sure they have folks in
there who have an understanding of all the different
steam generator designs. So we got a good, broad
perspective on it.
They know about the guidelines and the
policies. They've been talking about them. The peer
reviews: We have that going on through INPO. As
well, NEI 97-06 suggests peer reviews within its own
framework, separate from INPO. That also takes place
within SGMP when people use each other's expertise to
look at aspects of their program, help them get things
set up, help them maybe do a little bit better on this
part or some other part.
The organization interfaces to the NRC
through us, and maintains research and improvement
efforts all the time.
So that's the issue. Anymore questions on
what the industry is doing here with respect to this?
I want to get into a little now about what is this
regulatory approach all about. How did we get here,
and what does it mean?
As you probably know, the original
approach from the regulatory perspective was to put
out a rule. How am I doing on time? Do I need to
hurry this up or am I okay?
CHAIRMAN FORD: Was your plan to go from
-- You are currently on this Item 3. Is that right?
MR. RILEY: Yes, and I can skip over as
much as this as you want, and we can make it as quick
as you want. You wanted to spend some time on that
one. So I spent more than I was planning to. When do
you want me to be done, though?
MR. DUDLEY: In about three minutes.
MR. RILEY: Three minutes? All right.
Well, let's not talk about history then.
CHAIRMAN FORD: No more history.
MR. RILEY: Okay. No more history. Let
me talk a little about 97-06, because it's essential
to this thing. 97-06 is a document that's put out by
NEI. It establishes the framework for a steam
generator program.
It's an overall guidance document. It
does not provide the details. The guidelines provide
the details, but NEI 97-06 provides the direction. It
contains a lot of key issues, basically the whole
aspect of what is a steam generator program and what
does it consist of.
The next slide already talks about the
guidelines that are included within it. I want to go
into the initiative a little, because it's very
important.
Revision 0 of 97-06 was put out in 1997,
I guess, as its name might imply. That was followed
by an NSIAC initiative, and this is really important.
I told you what NSIAC is. When NSIAC decides to look
at what they call a formal initiative, they take a
vote on some policy.
Eighty percent of the chief nuclear
officers in this country agree with this policy. That
policy becomes a commitment to all the chief nuclear
officers in the country, and this is the commitment
that was voted on in 1997. It's in italics and in the
box:
"Each licensee will evaluate its existing
steam generator program and, where necessary, revise
and strengthen program attributes to meet the intent
of the guidance provided in NEI 97-06, Steam Generator
Program Guidelines, no later than the first refueling
outage starting after January 1, 1999."
In fact, 97-06 has been implemented at all
the plants, and it is part of the driving force behind
all this industry involvement that we see and
commitment to working together to make our programs
better.
97-06 is also a living document. It's
been revised once, I think you mentioned earlier, in
January of this year. We are working on Rev 2 right
now. The intention of both these revisions is to keep
it up to date with what the industry sees in the way
of a steam generator program, what we discuss with the
NRC, what new issues come up and get resolved.
I can move through the rest of these with
almost saying nothing about them. I told you about
TAG. This is just a reemphasis of the fact that we
have a lot of things going on with respect to
communications, that the industry is talking to each
other. People are aware of what is going on at other
plants, and we do so through the TAG organization in
the SGMP.
We already know, I think, about the
Generic License Change Package. We are in the middle
of revising it. I will say a little bit about some of
the issues that are going on with it. You know, or
maybe you don't know so I'll take a minute to tell
you, that the License Change Package really is, as its
name implies, everything you need to change your
license to be in compliance with this regulatory
framework we are developing.
It includes the regulatory framework. It
includes the steam generator tube integrity tech spec,
which basically says you will maintain steam generator
tube integrity and, if you have reason to believe you
got a problem with it, you got actions to take, and
you got surveillances to perform to verify that indeed
you do have integrity that involve inspecting and
plugging your tubes at certain intervals.
It has a bases associated with it, a
fairly detailed one that goes into a lot of
information on what we've done over the last couple of
years with the NRC to pull this thing together to give
people an understanding of where all these
requirements came from.
It includes change to the operational
leakage tech spec which you know governs primary,
secondary leakage. In fact, it requires 150 GPD
primary, secondary leakage level, which is a change
from what a lot of folks have in their tech specs
right now, and it reflects what we have discussed with
the NRC and what's in the primary, secondary leak
guideline.
It includes admin tech specs to place
controls on certain key elements of the program. In
fact, the issue of regulatory control of inspection
intervals is going to be resolved through this admin
tech spec. We are looking at how do we change
performance criteria, repair criteria, repair methods
and, in this case, inspection rules going forward.
Basically, what this sets up is a means to
do so. The NRC wants to have a part of the approval,
wants to approve these changes if they occur. Once
they have approved them, if they have approved them
generically, others can use them. But it kind of
keeps things under control with respect to these key
elements. That's in the admin tech spec.
It also includes significant hazards
evaluation, safety analysis. The intent is that, when
this is approved, it will be clipped. If you are
familiar with the clip process, which basically it
puts something out there for everybody, and other
plants can use it a lot quicker and avoid the whole
license amendment -- avoid the time involved in the
difficult license amendment process.
We hope to be able to clip the Generic
License Change Package when it's done, so plants will
be able to implement it relatively quickly.
Real quick here, inspection rules: We are
going to be talking about later, there's two aspects,
as Ted said. There is a regulatory control issue, and
there is a technical issue.
I think, with our meeting yesterday, we
are on the same beam with respect to regulatory
controls. Technical issues still need to be worked
out. We are going to talk to you about what we are
doing on inspection intervals. We are working with
the NRC on their comments.
So in general, I believe we've got a real
commitment within the industry to perform -- to make
our steam generator performance as good as it possibly
can be. It's living. It's viable. It's continuing,
and we are very proud of it, actually.
That's it. Questions?
CHAIRMAN FORD: Just to make -- so that I
am sure, as far as being proactive with what we do,
you are saying that -- I'm sure, Ted, you will jump in
and tell me if I'm wrong -- that you are agreed on the
regulatory aspects. Therefore, unless we decide
otherwise, do we just forget about regulatory aspects?
So it's only the technical issues from this point on
that we are interested in, the inspections of those --
these are the things that we are mainly interested
from this point on?
MR. SULLIVAN: Yes, and I might note that
the tech specs currently contain controls on
inspection intervals. So we are not inventing
something new here. It's more that we are carrying it
over into the new framework.
We weren't initially intending to do that,
but because of the concerns that the staff has with
the performance based approach, we want to carry that
over until we get those issues fully resolved. And
I'll discuss a little bit more, or whoever is going to
give this presentation will discuss a little bit more
some of the flexibility we are trying to build into
this admin tech spec so that we won't have to revise
the tech specs yet one more time to get rid of these
prescriptive maximum inspection intervals. That is
covered later on.
CHAIRMAN FORD: I noticed in the timing,
in the majority of the time left we are going to be
hearing primarily NRR's views on these technical
issues. And there's only ten minutes for the NEI to
argue against them. Is this what the wish was? I
mean, so we get a balanced view?
MR. DUDLEY: That's really up to you.
CHAIRMAN FORD: Well, the question is, has
NEI got the veto in the arguments? I know you guys
have gone through this backwards and forwards quite a
few times. Do you all have the data upon which these
technical issues are being argued backwards and
forwards?
MR. RILEY: We have an explanation of the
details of our guidelines on inspection intervals. We
didn't come here with a lot of detailed technical data
on the NRC comments. As a matter of fact, we are
still dispositioning their comments and developing
that technical data right now.
CHAIRMAN FORD: That's the things to do in
early next year. Is that right?
MR. RILEY: Well, yes. That's the thing
that we believe we want to have this guideline on the
street by the middle of next year, and our intent is
before that time that we will have responded to not
only the NRC comments but also the internal industry
comments.
CHAIRMAN FORD: So in your comments and
the NRR comments, we will hear both sides, what they
say and then what you dispute?
MR. SULLIVAN: I think so, and I think I
want to just add one thing and see if Jim Riley agrees
with me. When Jim was talking about putting together
the information in the time frame of the first -- you
know, between now and the middle of 2002, that's
information to address staff comments and their own
comments on inspection intervals. But over a longer
time period, I believe industry and the NRC are going
to be working together on other -- on technical issues
associated with the performance based approach, which
are issues that I'm going to touch on in this
presentation somewhat topically.
CHAIRMAN FORD: Okay. So if we ask
technical questions, you can both jump in. Yes?
MR. SULLIVAN: That's true.
CHAIRMAN FORD: Okay, let's roll. Thanks,
Jim.
MR. RILEY: Thank you.
MR. SULLIVAN: Okay. The fall-back plan
was that I was going to start this presentation. But
since Emmett is here, Emmett, you came in at the
perfect time. Now could you help us understand the
time frame here? Emmett is going for how long before
the break?
MR. DUDLEY: Right now, about half an
hour.
MR. SULLIVAN: Okay. We are on schedule.
CHAIRMAN FORD: Emmett, would you like to
-- Would it help you if we took a ten-minute break now
let you regain your breath?
MR. MURPHY: To collect my thoughts? I
wouldn't mind.
CHAIRMAN FORD: Excellent. Okay.
(Whereupon, the foregoing matter went off
the record at 9:29 a.m. and went back on the record at
9:41 a.m.)
CHAIRMAN FORD: Emmett, if you would like
to start, we would appreciate it.
MR. MURPHY: Okay. Well, thank you.
In September we briefed the Subcommittee
on the Steam Generator Change Package, describing some
background, outstanding issues, that kind of thing.
The Subcommittee expressed a desire to be briefed on
additional details of the outstanding issues in the
proposed resolution. So that is why I am here today.
I will jump quickly ahead perhaps to the
punchline of all of this, and that is there has been
in recent days and weeks considerable progress toward
reaching some sort of conceptual agreement on a
resolution path for resolving these issues and moving
on with the review of the Generic Change Package.
Now just to have for purposes of a
perspective on the revised generic framework that is
being proposed, it's helpful to remember where we are.
I don't think we have talked about this for a couple
of years.
Existing requirements are highly
prescriptive. Basically, you are required under
existing tech specs to inspect a specific number of
tubes at specific intervals, and you plug the
defective tubes that you find at a prescribed plugging
limit.
Typically, under the tech specs plants are
implementing a 24 calendar month inspection interval.
That can be extended to 40 months, to the extent that
there's not really a whole lot going on in your
generators.
MR. KRESS: Why not 48?
MR. MURPHY: These numbers date back to
the -- basically, to the mid-Seventies. Their origin,
prescribed origin and basis is obscure, but clearly --
Well, we'll just leave it there.
CHAIRMAN FORD: When you say degradation
activity is minimal, is there a metric to do that? I
mean the number of cracks or the depth of cracks?
MR. MURPHY: Yes, there is a metric in the
tech specs, precisely how many flaws that would get
you above a threshold beyond which you do more
frequent inspections and more inspections in general.
MR. SHACK: What is a guy with the 690
steam generator actually doing at the moment?
MR. MURPHY; It varies. Some now are
beginning to implement the 40 months, take advantage
of the 40 months interval allowed in the tech specs.
Historically, there were not many plants ever that
were able to take advantage of that, if for no other
reason, even if corrosion hadn't started yet, you
know, wear problems would --
MR. SHACK: Got nailed by something?
MR. MURPHY: So it's only been in recent
times that plants are really able to begin to take
advantage of this 40 month interval, and that's, you
know, plant with replacement generators with the more
modern designs that minimize wear problems.
MR. SHACK: Now what are they doing with
sample sizes, for example
MR. MURPHY: Sample sizes they do in
accordance with the guide -- Well, they meet the tech
specs, of course. That's no problem. The driving
force is what the EPRI guidelines say.
MR. SHACK: Okay, right. Right. So they
are all committed to that.
MR. MURPHY: Yes. Just one other
observation I think that's important to make is that
tech specs don't speak at all to inspection methods:
Eddy current, how do you do eddy current. There are
code requirements with respect to how you do eddy
current, but the improved inspection performance
through the years has really been driven largely by
technology improvements and improved industry practice
in accordance with industry guidelines.
I guess the point I wanted to make here is
that these are prescriptive requirements. Their
origin is obscure. There aren't -- One might ask do
these ensure that you maintain tube integrity. They
don't force you to ask yourself am I inspecting
frequently enough? Are the flaws that I'm finding
during inspection within a comfort zone that I'm
assured that I am maintaining adequate tube integrity?
The existing tech specs don't force you to ask that
question.
So one might ask then where are we from a
safety perspective today? The available evidence is
that steam generators are generally operated with
acceptable safety margins, consisting with the
licensing basis.
MR. KRESS: What does that mean? What
exactly does that mean?
MR. MURPHY: It means that typically, to
the best of our knowledge, steam generators are
operating while meeting margins of three with respect
to a burst under normal operating pressure.
MR. KRESS: Three with respect to --
MR. MURPHY: Yes. I mean, you know, we
might see one or two plants a year out of the fleet
that are -- during an inspection we find that they
have challenged that criteria. But in the main,
plants typically do not trip this criteria during
their operation. But, of course, there are
exceptions.
We would argue that they appear to be
relatively isolated occurrences. Exceptions include,
but are not limited to, the eight SGTR events that
have occurred. There are other events besides SGTR's
where we don't degrade to the point of failure, burst
during normal operation, but you know, you don't have
the margins you would like to have.
A recent example is TMI with the wear
associated with the severance of a plugged tube. The
other example recently was Arkansas Unit 2 where again
they didn't have a tube rupture during normal service,
but they didn't have the margins that -- the margin 3,
for example, at the end of the operating cycle.
So you know, available risk studies
indicate that from an industry-wide perspective the
risk is within acceptable levels. As you know, there
is ongoing work in this area as part of the SG Action
Plan, in part responding to some of the concerns that
ACRS has with respect to risk, steam generator risk.
MR. KRESS: Remind me what an acceptable
level is.
MR. MURPHY: I'm not sure. I can't give
you the precise numbers, but acceptable levels in
terms of the available estimates on the core melt
frequency and LERF. Both those considerations were
looked at. The best --
MR. KRESS: In reg guide 174?
MR. MURPHY: Forgive me?
MR. KRESS: The values in Reg Guide 1.174?
MR. MURPHY: Yes. Yes. The available
risk studies today would indicate that risk from steam
generator related events are not a significant
contributor to core melt risk or LERF.
Steve, do you want to add to that?
MR. LONG: This is Steve Long with the NRC
staff. I think I understood your question was related
to the slides saying that the risk studies have
indicated that the risk from SG related causes are
within acceptable levels.
MR. KRESS: Basically, what?
MR. LONG: We've been doing PRAs for
sometime, and steam generator tube rupture since -- It
really wasn't included in WASH 1400, but since then
it's been there. It's been a fairly small contributor
to the core damage frequency, but it's been one of the
major contributors to the off-site consequences.
That's what attracts our attention to it, to try to
make sure that we maintain adequate control of the
tube integrity, because we don't want that number to
go up.
We have accepted the numbers we've been
finding. In terms of whether or not we would like to
see changes in them, that usually gets into a backfit
consideration: Is the change worth the cost in terms
of dollars or operational exposure or whatever?
As late as NUREG 1570 in the middle of the
1990s, we were looking at what we thought the risk
was, including the severe accident risk and what we
thought some of the changes that the industry was
requesting at the time might mean in terms of severe
accident risk and other risks.
I think we continue to conclude that with
the regulatory framework we are trying to enforce now
that the risk is pretty much where we have thought it
was and accepted in the past, which is probability of
core damage that is in the low
10-6 range from all the degradation mechanisms, and a
probability of -- The definition of LERF is kind of
hard to deal with -- a combination of core damage with
containment bypass through tube failure. It's in the
10-6 range.
We've been accepting that all along. So
I guess that is our definition, at least, of something
that is so far acceptable.
MR. BONACA: Those are the values we
looked at for the BPR in the NUREG?
MR. LONG: Now in 1570 we also looked at
what might be the implications for some things like
allowing steam generator tube leakage during
depressurization transients to go maybe 100 BPM or
higher. We concluded we didn't know enough to say
that that would remain acceptable. We needed to know
more.
So we think what we are enforcing now is
acceptable. We are not sure about some of the things
that would be economically beneficial to allow but
maybe not acceptable safety if we allowed them.
MR. MURPHY: Thanks, Steve. Okay. safety
record to date reflects two things. One, it does, to
some extent, of course, reflect existing requirements,
and we would argue, in particular, it reflects the
tight requirement on inspection intervals that
currently reside in the tech specs.
Arguably, if that's all there was, that
would have been sufficient, that clearly, a very
significant factor in the overall safety record of
steam generators through the years have been industry
initiatives that have been and guidelines embodied in
industry guidelines that have resulted in industry
actions in excess of minimum requirements.
These industry practices have resided in
industry guidelines. Some of the more powerful
influences on experience through the years have been
the water chemistry guidelines and SG examination
guidelines. These have had a tremendous influence
through the years in reducing the level of --
minimizing corrosion problems or reducing them to
levels that we experienced early on, and resulting in
the application of more sensitive eddy current
inspection methods toward detecting these problems and
detecting them early.
MR. KRESS: What message are we supposed
to get from that, that industry takes it seriously?
MR. MURPHY: The industry takes it
seriously, but I think that one of the things we are
getting to -- where's my previous slide?
MR. KRESS: The one just before?
MR. MURPHY: What we are going to do --
What has been proposed is to -- We are going to
eliminate current requirements, and essentially we are
going to rely on a framework that is built around
industry guidelines.
So then the question is: Is a regulatory
framework built around industry guidelines -- is that
adequate to do the job? to what extent has the safety
record to date been a function of both? Actually, we
think it's been a function of both, and when we move
to the new regulatory framework, we have to keep in
mind what's been helping us out in the past, make sure
that we are adequately covered in that respect.
One of the major issues in this respect,
I think, is the 24 month inspection interval. It's
only been just recently the industry issued its tube
integrity assessment guidelines, guidelines allowing
you to predict how much safety margin you have now
based on your inspection results and to predict where
you are going to be at the time of your next
inspection, how much safety margin you are going to
have -- or tube integrity margin you are going to have
then.
We think that these guidelines need
further development before they going to be fully
effective. I think the major concerns, not the only
concerns but the major concerns at this point, are the
ability to project, based upon current inspection
results -- the ability to project where you are going
to be tube integrity-wise at the time you do your next
inspection.
Okay. So we are on to -- Under the
proposed, industry proposed Generic Change Package, we
are essentially going to delete the existing
prescriptive requirements and replace them with this:
"An SG program shall be established and implemented to
ensure SG tube integrity performance criteria are
maintained."
MR. KRESS: Integrity performance criteria
-- Could you spell out what those are?
MR. MURPHY: Yes, I'll get -- As a matter
of fact, I'll give you a brief summary of what those
performance criteria look like, but the performance
criteria are identified in the SG Program which is
outside of the tech specs. They are also identified
in NEI 97-06.
MR. KRESS: Are they the same for every
plant?
MR. MURPHY: They will be -- In general,
they will be the same for every plant. There is an
admin tech spec that says that, if people want to
implement different performance criteria, they have to
come to NRC for review and approval.
The details of the SG Program, of course,
as Ted talked about in September during the earlier
meeting with you -- Details of that program are
outside of tech specs, and these programs will
generally be developed in accordance with the industry
guidelines that we talked about earlier. But the
admin tech spec will require periodic condition
monitoring of the tubing relative to the performance
criteria every time you do an SG inspection. This
requirement, of course, does not specify how
frequently you will be inspecting or how frequently
you will be doing condition monitoring.
Basically, this is a performance based
approach. Performance criteria are identified.
Periodically, you are assessing the condition
relative to this performance criteria.
The performance criteria we've talked
about in past years with this Subcommittee. Just as a
brief refresher, they include -- Under the heading of
structural criteria, they include maintaining a factor
of three against burst under normal full power
operating conditions. Also includes maintaining a
factor of 1.4 against burst for accident conditions.
That's the structural criteria. There's
also an accident induced leakage criteria, which is
applied to the population of tubes. Under this
criteria accident leakage from the population shall
not exceed that assumed in the licensing basis
accident analysis. In addition, it should not exceed
a number such as 1 gpm, which is normally assumed in
the licensing basis, except as approved by NRC.
This criteria is intended to ensure that,
even if one is using a number within the licensing
basis, one is not using a number that might have
potential risk implications, that if you are going to
-- If your leakage criteria is going to be 1 gpm, you
need to be risk informed, and that's what this
criteria is about.
There are a number of plants out there,
for example, that utilize -- that have done accident
analyses to justify leakage numbers on the order of 15
gpm, 20 gpm, under accident conditions.
These numbers are consistent with
maintaining a small fraction of Part 100, those
limits, during a design basis steam line break. But
we also had to -- You know, the staff determined that
provided this leakage was coming from -- that the
calculated leakage was coming exclusively from cracks
at tube support plates, that there shouldn't be any
severe implications.
It wouldn't be acceptable, for example, to
have free span cracks leaking at this amount, the
difference being that actual leakage under steam line
break conditions from cracks at the tube support
plates are believed to be substantially less than what
were calculated.
CHAIRMAN FORD: Before you move on, do I
understand that these are the criteria that are
currently in the 97-06 Rev 1?
MR. MURPHY: That's correct.
CHAIRMAN FORD: And you approve of it, and
no problems at all with these?
MR. MURPHY: These criteria were arrived
at through a consensus reaching process with industry.
So I guess it would be fair to say we negotiated these
criteria with the industry.
CHAIRMAN FORD: So when I see in the
various memoranda a question about the factor of 1.4,
for instance, that as of today is no longer an issue?
MR. MURPHY: No. We were recently
informed by NEI that one or two of the NSSS vendors
who were asked to comment had a potential difficulty
with the 1.4 as it applies to differential thermal
stresses, and that they may seek a proposed refinement
or revision to this criteria. Maybe this criteria, in
their mind, needs some clarification.
Other than being alerted to the fact that
there's a potential issue here, we have not been --
The industry has not submitted their position, their
revised position, on this point yet.
So to the extent that -- You know, we
expect that the industry is going to come at us in a
few weeks and say, look, we have these comments with
respect to that criteria, and this is what we think we
need to do about it.
CHAIRMAN FORD: But what is the technical
basis for your approving these criteria, and also the
operation that you speak of, I think, has changed, is
it not, from 500 to 150?
MR. MURPHY: Well, as I said, you know, we
-- The criteria, as they exist as of this point, were
believed -- They were developed with the belief that
they were consistent with the existing licensing
basis. For example, we believe that they were
consistent with the safety factors that went into the
development of the 40 percent plugging limit in the
existing tech specs.
So the dogma behind the development of the
performance criteria was to try to maintain
consistency with the structural margins and the
leakage margins that we have been maintaining all
along, not to cut back relative to those margins.
That was the goal. That was the goal
behind the development of the performance criteria.
Now there's a suggestion out there that perhaps we
didn't quite succeed with respect to all the
applications of the 1.4 safety margin for accidents.
It's a little bit early for me to react to
that until I see exactly what kind of position the
industry is developing on this. But this is -- You
know, this was something we arrived at a couple of
years ago, and --
CHAIRMAN FORD: I guess I keep coming back
to next week when you make a presentation at the full
Committee of the ACRS. Do I take it that those lists
of things you've got up there -- there's a sound
technical basis for having approved them?
MR. MURPHY: Yes, I think they are
conservative. I think there's, you know --
CHAIRMAN FORD: So if someone on the full
Committee asks, well, where is your data to justify
that approval, that could be shown?
MR. MURPHY: We would certainly be
prepared to discuss the basis for these performance
criteria, and I think the industry concern with
respect to the 1.4 is that, with respect to
differential thermal stresses, the safety factor is
over-conservative, that we need to --
CHAIRMAN FORD: I guess we are taking a
lot on faith here. We've really been asked as a group
here to put our signature that, hey, this is okay, and
yet we have seen no evidence that it is okay.
MR. BONACA: I have a question on that, if
I may. Accidents that you are talking about, I mean,
what conditions are they assuming to measure against
at a 1.4 factor? Could you put up that slide again?
MR. MURPHY: Yes.
MR. BONACA: Seems now that number is
supposed to be conservative. What puts that an
accident? I mean, any accident, any over-pressure?
MR. MURPHY: Any design basis --
typically, main steam line break is the most limiting
accident when dealing with steam generator tubes, and
typically the main loading that needs to be considered
for that condition is differential pressure that may
exist across the tubes, typically on the order of 2500
psi.
For plants such as -- For B&W type
generators, tubes also tend to experience a high
degree of tension with respect to -- you know, during
the cool-down part of the transient. These are
thermally induced stresses.
The code requirement for faulty
conditions, of course, were not -- The code equations
or the code limits apply to primary stresses, not to
secondary stresses. There's some question as to what
this 1.4 means with respect to the treatment of axial
stresses in B&W tubes.
If one applies this -- It's maintained at
applying this directly to -- To thermal stresses, it's
over-conservative. There needs to be a different
treatment with respect to thermal stresses, and this
is the issue I think the industry wants to take up
with us.
MR. SULLIVAN: It might be worth it to tie
this into the ASME code also. We're getting a little
bit of question about the soundness of these criteria.
They originally came from the code.
MR. MURPHY: Yes. There is an assumption
-- There's an assumption in the design rules, Section
3 design rules, that a one-time application of thermal
stress cannot lead to component failure, and that's
fully appropriate for design conditions. But if we
are talking about a long tube with a circ crack under
a significant axial load, a thermally induced axial
load, that may no longer be an appropriate assumption
to make.
That is, a large axial load, thermally
induced axial load, could well --
CHAIRMAN FORD: What would the likelihood
of there being such a thermally induced axial load be?
MR. MURPHY: Oh, it will occur.
CHAIRMAN FORD: So, in fact, that is not
necessarily -- If you want to put a probability
against it, that criteria is not absolutely safe. I
don't know how you qualify that, but it could occur.
You could get burst even by maintaining that criteria
of a factor of 1.4.
MR. MURPHY: Actually, I think what is
being maintained is -- and we haven't heard the
position yet from the industry, but I think what is
being maintained is that applying this factor to a
different thermal load leads to overconservatism.
CHAIRMAN FORD: I guess that's the nub of
my question. We are being asked to -- or the
Committee will be being asked next week to say, hey,
yeah, we bless this. But you have already said that
that is not an absolute guaranty that you will not get
a catastrophic 360 degree burst.
MR. MURPHY: No. I think that --
CHAIRMAN FORD: Therefore, what would the
consequence of that be? I need guidance from my
colleagues here. Am I pushing this too much?
MR. SHACK; Well, I think the answer you
are looking for is that those factors really come out
of the implied factors that are in the code. Those
are kind of the implied structural integrity factors
that the code has.
Now the code didn't really mean to sort of
imply them to defective -- You know, the code assumes
that you didn't have defective structures. So this is
kind of a pseudo ASME limit, but that was really the
intent of the code, was to provide a significant
margin against burst under normal conditions, which is
three, and then under accident conditions, which are
presumably not going to occur nearly as often. They
were willing to back off, and so they came down to the
1.4.
Now the question is: Typically, the code
has different allowances for thermal stresses for
secondary stresses than they do primary stresses,
simply because a little bit of deformation relieves
the secondary stress. I guess the question here is
whether you are going to -- They are nominally
treating this differential thermal expansion now as a
primary stress when you apply the 1.4, I guess, is the
argument that you are getting.
MR. MURPHY: Yes.
MR. SHACK: Whether that's appropriate or
not.
CHAIRMAN FORD: But for an non-defective
tube, you said.
MR. SHACK; Even for a defective tube, you
know, the -- I would argue that the three and the 1.4
come from code limits. Now the discussion as to
whether this applies to the differential thermal
stress sort of has to come back to a discussion of
whether you think in this particular case the
differential thermal stresses are acting like
secondary stresses or they are acting like primary
stresses.
You know, we normally think of thermal
stresses as being secondary stresses, but sometimes
there is a -- they act a whole lot like primary
stresses, and sometimes they don't. So that's
presumably the discussion that comes in as to whether
you maintain this on the differential thermal stresses
or not. But the factors of the three and the 1.4 are
essentially derived from the code.
CHAIRMAN FORD: What I would suggest is,
rather than belabor this an take up all the time,
bearing in mind that we will be talking next week
about this whole thing in a condensed fashion, you may
well be asked a question, what is your technical basis
for making this approval, and the ASME code were
based, I understand, on undefected tubes. So --
MR. MURPHY: Let me just give you this
answer. I think it's the same answer I'll give next
week. These limits were intended to be consistent not
just with the licensing basis as well as the original
design basis of the tubes in Section 3 of the code.
The margin criteria here were derived from the Section
3 stress limits, even though the stress limits are
developed -- are to be used for design space, and we
are applying these to an operational situation where
the components have cracks.
I think the way these criteria presently
read -- The performance criteria, I think that they
represent a conservative set of criteria with respect
to accident situations. I think what we are going to
hear from the industry in the future is that they are
over-conservative with respect to how one ought to be
treating thermal stresses and that maybe the 1.4 will
continue to be applied to primary stresses in the
tubing, that perhaps we need to do something --
consider the differential thermal stresses in a little
bit different way, not applying this factor of 1.4.
CHAIRMAN FORD: Well, I think there's been
some tests done, have there not been, on burst
pressures for defective tubes? Can you not use that
data as support for this contention, and also to
support industry if that is going to be their argument
that these original curbs are overconservative? I'm
trying to help you in terms of convincing an
independent review body.
MR. MURPHY: Well, I think there's a lot
of test data with respect to the burst strength of
tubing and how it varies with the size of the flaws
and the orientation of flaws in the tubing. There's
certainly a lot of data there.
I think the available body of evidence is
that the sort of safety margins that we are talking
about, the factor of three and the factor of 1.4, are
generally sufficient safety margins that through the
years have been successful in minimizing any safety or
risk implications with the actual condition of the
generators.
So that the safety margins appear to be
sufficient based on experience. The goal is being
consistent with the code. Yes?
MR. LONG: Can I add one other thought.
This is Steve Long with the NRC staff again.
You had asked earlier in the presentations
about severe accident issues. One of the things that
we are counting on to maintain the tube integrity
during severe accidents are these margins.
So when we think about the adequacy of the
margins, we need to think about them with regard to
all the challenges that relate to the risk equations,
and some of those are higher than normal operating
temperature and various delta P's.
So when you get into whether or not this
is overly conservative or maybe not quite conservative
enough for some reactor designs which get to fairly
high temperatures in the tubes during severe
accidents, we are not quite sure yet.
For some of the designs it looks like
we've got enough margin here. Maybe for some we don't
quite have enough margin at three times normal
operating pressure as the strength requirement for
normal operating temperatures.
So it's a little more debatable than it
would sound when you just stuck to the design basis
conditions. We are still doing research to try to
nail it down a little bit better.
CHAIRMAN FORD: Recognize where I'm coming
from. I'm coming from an ACRS member that's been
asked to stamp your conclusions, not having seen the
detailed technical case you have made for making those
conclusions. I don't doubt you have a good argument,
but this makes you feel good to see some data that
backs up -- as a back-up. Have a back-up slide next
week to show that, hey, you've thought about this.
MR. BONACA: I have just one last question
I want to ask about this. The guidelines -- They
consider the possibility that you have -- during the
cycle. Okay, not necessarily a similar break. But
you have cool-downs and heat-ups.
MR. MURPHY; Yes.
MR. BONACA: And they will place some
stress on the tubes, and will it affect the
temperature in some way? I mean, there are
considerations of that in the guideline?
MR. MURPHY: Well, of course, the design
rules in Section 3 consider that. You have the
different service level stress limits. In fact, years
ago when discussing with the industry what the
performance criteria should look like, we had proposed
that there should be different safety factors,
dependent upon whether we were talking about service
level A, B, C type loadings.
The industry maintained that that would be
going beyond the existing licensing basis, that if one
looks at the 40 percent plugging limit, and if one
looks at the factors of safety that are implicit in
the 40 percent plugging limit, that while those
factors of safety -- while you are maintaining a
factor of safety of three with respect to operation at
normal full power steady state operation, that in fact
during a heat-up, cool-down or other operational
transient, you might actually have less than a factor
of three.
Apart from the performance criteria
themselves in NEI 97-06, the guidelines -- the
industry guidelines go into additional detail about
how licensees should assess structural integrity. it
talks about consideration of these other operational
transients, making sure, for example, that you don't
exceed the no yield criterion.
You know, you need to -- These are -- and
I guess one might say, to some extent, these criteria
that I presented on the previous slide are sort of the
criteria that the guidelines do contain additional
details about the kinds of evaluations people should
do to assess structural and leakage integrity.
CHAIRMAN FORD: Emmett, I noticed you've
skipped one slide. Would you mind going back to the
steam generator program, a request, actually. I
understood from Jim's earlier comment that the second
bullet that makes reference to detailed EPRI
guidelines.
Could I suggest that maybe you have a sub-
bullet in there making note of the fact that they
agree that these are living documents. I'm aware that
-- environmental degradation in the whole light water
reactor business. We are forever learning, and new
data will come along, and those EPRI guidelines are a
living document.
MR. MURPHY: All right.
CHAIRMAN FORD: It would be worthwhile
pointing this out, because if you come back to this
thing in ten years' time, there could be --
MR. MURPHY: All right. Point taken. in
fact, I was going to get into that a little bit later.
CHAIRMAN FORD: Oh, okay. Fine.
MR. MURPHY; But at this point, obviously,
I am going to be reconstructing this presentation as
I go along.
CHAIRMAN FORD: That would have been
helpful there. That's the first thing I want to say.
MR. MURPHY: Here it is. Okay. So we are
going to have an admin tech spec that says you are
going to implement a program to ensure that the
performance criteria maintained, and you are going to
periodically condition monitor the tubing to ensure
the fact that you are meeting the performance
criteria.
This is really an embodiment, in our mind,
of criterion 16 of 10 CFR 50, Appendix B, namely,
which specifies that measures shall be established to
ensure that conditions adverse to quality are promptly
detected and corrected.
Condition monitoring programs must be
capable of meeting this requirement. They've got to
be able -- Condition monitoring programs have to be
able to promptly detect the condition of the tubing
which was not meeting performance criteria.
Performance criteria, of course, should
represent tolerable conditions, if one is in a
performance based -- implementing a performance based
strategy, and that is -- we hold that that is true
also for the performance criteria that are part of
this Generic Change Package. But this is all premised
on the fact that, if you do exceed these performance
criteria, that that kind of condition is promptly
detected.
To the extent that you continue to eat
away at your safety margins after you have exceeded
the performance criteria, at some point, you know, you
are getting into a difficulty from the safety
perspective. So it's critical that condition
monitoring be capable of promptly detecting such
conditions.
So the question for us, the staff, as we
look at the Generic change Package is: Is there
enough here, not just with respect to the admin tech
specs but with respect to the industry guidelines,
that give us assurance that the programs, the SG
programs the utilities will be implementing will be
able to promptly detect and correct such conditions.
I would like to move on to slide 11
briefly.
(Slide change.)
MR. MURPHY: The current version of the
EPRI guidelines with respect to examination
requirements is Rev 5, which was issued in 1997. They
provide for two different approaches, potential
approaches, for determining the appropriate cycle
length.
One is a prescriptive approach, which is
not all that different from what we have today under
existing requirements. In general, you inspect every
fuel cycle unless you've had minimal problems, in
which case you can go for two cycles.
There is also conceptually in Rev 5 a
performance based approach that says that you can use
operational assessment to look ahead and determine how
long you can operate the steam generators before you
predict that you would exceed the performance
criteria, and then you would set your inspection
interval on that basis, but the inspection interval
could not exceed two fuel cycles.
So that is the current version of the
industry guidelines, and in that respect they are not
too different from where we are today with existing
requirements.
I'm going to skip the next few slides.
CHAIRMAN FORD: Just to -- I'm trying to
tie it in with what Jim was saying. He said that this
essentially -- What you say here is essentially not
the 97-06, and Jim said 97-06 is already applied. Is
that correct?
MR. MURPHY: NEI 97-06 is already being
implemented by utilities. Utilities are also -- As
part of that effort, even before NEI 97-06, utilities
have been implementing these examination guidelines,
and since '97, of course, they have been implementing
Revision 5 of the examination guidelines.
CHAIRMAN FORD: And they are not going
against the original regulatory prescriptive formulas?
MR. MURPHY: Correct. That is correct.
And so they are subject to the criteria of the
guidelines. In addition, they are subject to
regulatory requirements. Where we're going with this
presentation is industry basically wants to move from
Revision 5 to Revision 6 of the guidelines. That is
going to allow for longer operating intervals. Okay?
So to get there, industry needs this
revised regulatory framework, because right now they
are constrained by the regulatory requirement for 24
month to a 40 month inspection interval, and they need
-- they would like to dispense with that.
With respect to the ability of condition
monitoring to fulfill its Appendix B obligation, there
are a number of guidelines that are relevant to that
capability. One of them is the examination
guidelines, of course.
Also the tube integrity assessment
guidelines which give guidelines for doing operational
assessments, guidelines for doing condition monitoring
assessments are relevant. Also industry guidelines
with respect to in situ pressure testing, which is a
component of condition monitoring, are relevant to the
capability of condition monitoring to fulfill its
Appendix B obligation.
(Slide change.)
MR. MURPHY: I'm at Slide 15.
CHAIRMAN FORD: Just to make sure that I'm
calibrated. So far we haven't heard anything -- You
haven't touched on any of the technical issues that
currently exist. Is that correct?
MR. MURPHY: That's correct. It had not
initially been our intent to formally review or to
endorse the sub-tier detailed EPRI guideline documents
such as the examination guidelines, the tube integrity
assessment guidelines, that kind of thing.
It had been our expectation that the
guidelines would be sufficiently well developed to
lead to improved tube integrity performance within the
context of the new regulatory framework being
proposed. We knew that there were going to be issues,
outstanding issues, with respect to the guidelines,
but these issues were issues that have existed all
along. These are not issues introduced by the new
framework and issues that are not unique to the
revised framework.
It was our expectation -- I think this
responds to one of the questions earlier -- that the
guidelines would continue to evolve over time. They
are living documents in response to identified issues,
technology changes, lessons learned from operating
experience, and the results of industry and NRC
studies, such as the NRC SG round robin study, the
action plan including the work that's being done to
address some of the ACRS comments with respect to the
DPO.
Findings from all of these activities will
influence the future course of these guidelines over
time. There's no question about that.
MR. SHACK: Have you formally reviewed
your Revs 3, 4, 5 with respect to inspection
guidelines?
MR. MURPHY: We never formally reviewed
the guidelines. We always read the guidelines, tried
to know what's in there, but they were never submitted
for our formal review and approval, and we have never
gone through a formal process like that with respect
to the guidelines.
MR. SHACK: But an inspector sort of
accepts them as an acceptable Appendix B approach to
quality assurance for the examination? Is that your
regulatory tool for looking at these procedures?
MR. MURPHY: In general, in today's
regulatory -- under today's regulatory requirements,
the plants are not inspected relative to the
guidelines. Their adherence to the guidelines is an
industry initiative.
Now in a case such as Indian Point where
it became clear that past inspections leading up to
the failure at Indian Point were not as effective as
we would like to have been, we certainly looked at
utility actions with respect to industry guidelines
prevailing at the time the last inspections were
performed.
If one is making judgments about the
reasonableness of licensee actions at any point time
in time, you know, questions of how well they are
adhering to available guidance may be relevant in that
context.
Okay. We knew there were going to be
issues with respect to the guidelines.
MR. BONACA: Could I ask just one thing?
I know we already talked about Slide 8, and I want to
go back to the criteria. As I reflect on this,
clearly, a much higher burden is being placed on the
criteria than ever before. Before you had intervals
that were based on the prescriptive.
There was some relationship between, for
example, the first criteria and the interval, but it
really wasn't so tied together; because you had
prescriptive intervals by which you were inspecting
the plant.
Now you are performance based. Really, it
seems to me that they are going to set the intervals,
testing, inspection frequency based on these criteria.
So I think it is very important for next week that we
get a real understanding about the adequacy of the
criteria -- So why do you feel they are acceptable?
-- and adequacy of what you have to do to measure that
to the criteria.
What I've seen for the past three or four
slides is that they clearly will be able to set their
pace for inspections based on some way in which they
measure that they in fact exceed the 1.4 burst
pressure for transients or -- There is a lot of burden
placed on this criteria now. Formerly, there wasn't.
You know, I never thought of this criteria
as a burden on them. I never felt that way, because
they were like, yeah, the code says that. But really,
you do the inspection at a given time, and that's all
that's important.
Now everything is going to depend on these
criteria. So how credible are they as criteria, and
I'm sure they are, and what ways do they propose to
measure to those criteria? Are they acceptable ways
to measure or are we going to have other stuff coming
to us without an understanding?
MR. RILEY: Can I say something to that?
This is Jim Riley from NEI.
Maybe this might clarify it a little bit,
and Mohamad is going to provide a lot more detail.
Our guidelines have two ways of establishing the
inspection rules. One is a prescriptive based method,
and the second is performance based.
What we are discussing as part of the
Generic License Change Package right now, and what the
NRC has comments on are prescriptive based inspection
intervals which do specify intervals. They are a
little longer than what is currently in there, but
they are still defined intervals. It's a function of
the steam generator tubing materials.
They have to be supported at the same time
by an operational assessment. So they lay out the
specific lengths of time, but you have to be able to
show by an OA that indeed you can make those -- that
length of time.
Rev. 6 also includes a performance based
inspection interval, which is along the lines of what
you are discussing now. The length is purely
determined by how good you can do at predicting where
you will be at one time with respect to the
performance criteria.
The initial version of the Generic License
Change Package will not be adopting those performance
based intervals. it will be the prescriptive based
intervals that we are focusing on. We do want to use
those performance based, but we recognize we have more
work to do in terms of developing the justification
with the NRC.
MR. BONACA: I appreciate you are doing it
in a step-wise way, but since you are going in that
direction, try to answer and focus the question next
week. You know, a lot of burden is placed on these
criteria, and it is going to be. All right.
MR. MURPHY: Okay.
MR. SHACK; Just a moment. You know, one
of the things that's always puzzled me is that you
guys have been doing these operational assessments,
monitorings now for umpty-ump years, and we never see
comparisons of how well you are doing. If you
condition monitoring said that, you know, the largest
crack was going to be something or other, your
condition monitoring said --
MR. MURPHY: Well, Bill, actually, on one
of the next few slides here, that very point is made.
That is one of the issues that we have identified as
being something where -- one area where the guidelines
can be improved, a better benchmarking of operational
assessment relative to what you actually find later on
in revising -- you know, the feedback loop, and
refining the models based on experience.
I was going to get into a lot of details
of the issues that currently reside in the guidelines.
Suffice it to say for purposes of this morning's
discussion that we believe that there are a lot of
areas where the guidelines can be improved and be made
more effective. And I would just like to leave it at
that and move on.
CHAIRMAN FORD: When you say the
guidelines, these are the ones that you are going to
talk about? Okay. Since there are issues, I'm not
too sure what order you should go. After you give
your talk, Emmett, will you give a presentation on
your issues of this Rev. 6?
MR. MURPHY: I was going to push on to --
What was proposing to do now was to not get into a
discussion as planned on issues relating to the
guidelines that were more general than the Rev. 6
issues.
I would rather at this point just move on
to Rev. 6, and simply point out that, quite apart from
Rev. 6, there are a number of issues that exist with
respect to the industry guidelines that we need to
work through the years in firming up, making it
better and more effective.
(Slide change)
MR. MURPHY: During an NRC sponsored
senior workshop in February of 2001, industry
representatives made a presentation on work being done
to prepare a Rev. 6 of the steam generator examination
guidelines, and they caught our attention with their
plans for revising the inspection criteria for the
steam generator, particularly with respect to steam
generators with Alloy 600 thermally treated and 690
thermally treated tubing, primarily the tubing in
replacement generators, that they anticipated
substantially longer inspection intervals than what
exist either in current regulatory requirements or in
Rev. 5 of the guidelines.
At the time of the February meeting, the
prescriptive criteria they were proposing would have
provided for inspection intervals on the order of five
to six effective full power years with respect to
Alloy 600 thermally treated tubing and six to seven
effective full power years for 690 tubing.
There's been considerable interaction of
the NRC with the industry over the intervening time.
More recently, the industry has revised this
proposal, and now would include a two-cycle limitation
with respect to inspection intervals for 600 thermally
treated tubing and a three-cycle limitation, fuel
cycle limitation, with respect to 690 tubing.
(Slide change)
MR. BONACA: How do you go to from five to
six or six/seven to two or three. Seems such a
disparity of opinion.
MR. MURPHY: Well, you know, this bears
mentioning. A fuel cycle in this country generally
ranges anywhere -- depends on the plant -- from 12
effective full power months to 22 effective full power
months.
So maybe 18 is -- One might say 18 is
typical. So a two-cycle limitation for the 600
thermally treated tubing is quite a bit less than the
five to six effective full power years we're talking
about here.
CHAIRMAN FORD: Now this is what you will
be talking about, the arguments for these?
MR. BEHRAVESH; Yes.
MR. MURPHY: And when will you be doing
that, Mohamad?
CHAIRMAN FORD: After you.
MR. MURPHY: That's right. This is your
-- Okay, I understand.
Okay. Under the performance based
approach, the Rev. 6 would have dispensed with the
two-cycle limitation and, basically, the inspection
intervals could be as long as whatever could be
supported with an operational assessment or
degradation assessment.
Just based upon curves that are applicable
to the anticipation of corrosion mechanisms, we were
talking about inspection intervals potentially ranging
up to 20 years or so, assuming that something like
wear wasn't a more imminent concern.
So, clearly, here at this point, what we
saw was that there were going to be future changes to
the guidelines where there were going to be
potentially substantially longer inspection intervals
than we had contemplated up to that point. Then the
question for us was is there sufficient guidance
available to the industry to ensure that condition
monitoring will take place frequently enough to
promptly alert us to situations where we don't meet
the performance criteria.
CHAIRMAN FORD: I'm a little bit confused
by these two, both 20 and 21. Do I understand it,
Rev. 6, there are two criteria, a prescriptive
criteria and a performance based criteria?
MR. MURPHY: There are two different
strategies, yes, for determining --
CHAIRMAN FORD: And you get your choice,
or what?
MR. MURPHY: Yes. Well, I think what the
industry had envisioned as they were developing these
guidelines was that, you know, we are moving to a
performance based regulatory framework, and that the
implementation details in the guidelines ultimately
should be performance based as well. I think that was
the thinking.
Now they did have prescriptive criteria
available, and you would still have to do condition
monitoring and operational assessments to demonstrate
that those prescriptive intervals were consistent with
meeting the performance criteria. You would still
have that obligation, but the performance based
approach allowed you to actually set the inspection
intervals consistent with -- to make it as long as you
could, consistent with meeting the performance
criteria.
CHAIRMAN FORD: And you will going through
the realism as to why you would choose one over the
other?
MR. BEHRAVESH: Yes.
CHAIRMAN FORD: And it will be plant
specific?
MR. BEHRAVESH: Mohamad Behravesh, EPRI.
I will be touching on all of these, realizing that all
of that will be done within the time span of ten
minutes.
CHAIRMAN FORD: Okay.
MR. SHACK: Let me be clear now. Are the
prescriptive criteria an option or they are a cap on
the performance assessment?
MR. MURPHY: No, they are not a cap. The
way the guidelines are written, utilities have a
choice.
MR. SHACK: Oh, they have a choice.
MR. MURPHY: They can implement the
prescriptive criteria or the performance based
criteria.
MR. BONACA: When you talked about
possibly ranging to 22 effective full power years --
well, maybe you will be talking about that. So I'll
withdraw my question and wait.
(Slide change.)
MR. MURPHY; Okay. Our concerns with
respect to what is being proposed for Rev. 6: We
believe that appropriate inspection/condition
monitoring intervals are critical to ensuring the
prompt detection of conditions not meeting performance
criteria.
We are concerned that certain of the
guidelines, the tube integrity assessment guidelines,
aspects of the in situ test guidelines, and the
examination guidelines, are not sufficiently well
developed to support inspection intervals
significantly longer than what is being implemented
under current requirements or other acceptable
alternatives, which I'll be talking about.
Further, industry may -- You know, the industry
proposal in February kind of revealed a vulnerability
we had of our regulatory framework -- of the proposed
regulatory framework, namely, even if we reach
agreement on what the guidelines say, industry may
revise the guidelines down the road, and we are not
going to review an approval loop on that.
Further, licensees themselves may not
follow the guidelines. They may deviate from those
guidelines. They can do that.
We need to be assured that the regulatory
framework -- We need to be assured that condition
monitoring will be capable of fulfilling its Appendix
B obligation. Got to be able to promptly detect
conditions that are not meeting the performance
criteria, and we've got to be assured that that's the
situation.
(Slide change.)
MR. MURPHY: Okay. I've talked about the
fact that we have numerous issues relating to the
guidelines that affect the tube integrity assessments.
Further, we believe that the guidelines for
operational assessment of active degradation
mechanisms are not sufficiently developed to be used
as a tool for directly determining acceptable
inspection interval extensions.
Further, degradation assessment guidelines
and the technical bases for these guidelines have not
been developed for ensuring that the initial
occurrence of new degradation mechanisms will not
cause performance criteria to be exceeded.
Historically, degradation assessments have
not really been -- People haven't been doing
degradation assessments in this way. It is assumed --
The current regulatory basis -- The current
requirements, prescriptive requirements, assume that,
if we have a new degradation mechanism, that the
prescribed inspection interval will ensure a timely
detection of that new mechanism, and it will be
maintaining the appropriate margins.
If plants are to operate for many years
between inspections, we now have to reckon with the
potential that there may be a degradation mechanism
about to initiate and to progress, and there will need
to be some ability to determine when such degradation
mechanisms might occur and over what period of time
that might begin to challenge the performance
criteria.
Right now, the guidelines do not contain
a lot of detail about how to do this, and there's not
much in the way of a technical basis for what guidance
is there at the present time.
Finally, the draft inspection interval
strategies for Rev 6 of the examination guidelines are
being -- they are still being finalized. They are
still dealing with industry comments as well as NRC
comments. They have lacked critical details, and the
technical justification has not been provided to NRC
staff.
MR. BONACA: When you say operational
assessment and you are talking about condition
monitoring inspections, tell me the difference. I
mean, what is included in an operational assessment?
MR. MURPHY: An operational assessment is
a forward look which, based upon what you know about
the condition of the generators today and what you
believe the corrosion rates are or the flaw growth
rates are, where do you anticipate you will be
relative to the performance criteria at the end of
your inspection interval?
Condition monitoring is looking backwards:
Did I -- Based upon the inspection results, did I
succeed over the last cycle in maintaining adequate
margin?
Both of these assessments are dealing
with known mechanisms, active mechanisms. You project
where you are going to be in an operational assessment
with the degradation mechanisms that you know are
taking place, and you don't account in an operational
assessment for degradation mechanisms you haven't seen
yet.
MR. BONACA: I was reflecting. On page 21
where you have the 22 effective full power years, and
now we are talking about operational assessment.
Okay, we'll talk about it later.
(Slide change.)
MR. MURPHY: Okay. Staff has interacted
extensively with the industry and proposed a
resolution path. We believe that predictive
methodologies for managing known degradation
mechanisms and for anticipating the occurrence of new
mechanisms need to be strengthened to support
implementation of inspection intervals significantly
exceeding current requirements or acceptable
alternatives.
We plan to work with the industry in
identifying the needed improvements to the guidelines.
In the meantime, inspection intervals -- We believe
that inspection intervals should be subject to
appropriate limitations based on experience and
consideration of the improved stress corrosion
performance expected with the 600 thermally treated
and 690 thermally treated tubing.
Such acceptable approaches might include,
for example, limitations similar to what we currently
have in tech specs in the way of operating intervals,
or other potential alternatives such as perhaps the
criteria that are being developed in the context of
Revision 6 of the guidelines.
We have commented extensively on the early
drafts of the guidelines. Industry is considering
those comments as they work on Revision 6 of the
guidelines with respect to inspection intervals, and
we would hope that this work will lead to something
that we think ensures that inspections -- that through
the condition monitoring process we will be able to
promptly detect conditions that are inconsistent with
meeting the performance criteria.
(Slide change.)
MR. MURPHY: Apart from the technical
issue as to what constitutes an appropriate inspection
interval, the staff has concluded there must be
appropriate regulatory controls with respect to
inspection intervals to ensure that the performance
criteria are maintained, that conditions failing to
satisfy these criteria are promptly detected and
corrected, and that risk is not increased.
(Slide change.)
MR. MURPHy: So staff proposed an
additional criterion for inclusion in the admin tech
specs, which would basically specify that no changes
relative to a reference inspection interval criteria
that we have reached a consensus on -- that no changes
to such a criterion could be made without NRC review
and approval.
So you know, as industry refines the
guidelines, ultimately perhaps coming out with a
rigorous performance based approach for determining
how long inspection intervals can be, they would have
to come at NRC with such a proposal and get our review
and approval before licensees would be able to
implement such a approach.
CHAIRMAN FORD: Could I suggest -- I've
just been flipping through the remaining ones you have
and looking at the time. It seems to me that your
last four or five overviews are primarily just
recording some of the history of the industry and the
NRR responses to this.
I think that should be given -- It's
factual, but it doesn't add to the debate, technical
debate, that we have going on, what the issues are,
outstanding issues. As I understand it, we have re-
raised the issue about the 1.4 and the factor of three
for defective tubes. We are not too sure the depth --
the technical basis behind that agreement.
The other one, the big outstanding one, is
this whole question of the performance based
inspection. Periodicity is the big, outstanding
technical issue. Am I correct?
MR. MURPHY: No, we don't believe that the
guidelines support as yet a performance based strategy
for setting inspection intervals, but not only that.
The guidelines are not yet able to support
prescriptive criteria that are vastly different from
what is being implemented today.
So it's both. We have concerns about some
of the initial proposals that were made with respect
to prescriptive criteria, as well as having concern
about the performance based.
CHAIRMAN FORD: We've seen verbally on
your overgraphs what some of your concerns were on
those two issues, the prescriptive and the performance
based inspection interval. Could I suggest, looking
at the time, I want to leave at least -- We have one
more hour. I want to leave at least quarter of an
hour for subcommittee members just to give their
opinions about how you can enhance the presentation
for next week, and I want to have as much time as
possible to hear your views on the really outstanding
issue, which is the inspection.
So would you mine, Emmett, yielding the --
I'm getting real good at this parliamentary language
here -- yielding the podium to our friend to hear
their arguments?
MR. SULLIVAN: Dr. Ford, I wonder if I
could just add a minute or two. I'm not sure if this
will be useful, but --
You know, I hear the comments that have
been made by several members about your concern and
interest in the adequacy of the performance criteria,
and I don't think that comes as a complete surprise.
I know Emmett and I over the years have had a number
of conversations expecting interest in that area.
We didn't really come today prepared to
talk about that in detail, and I think what I'd like
to do is just try to shed a little bit of perspective
on why.
I think that there are two points, one
Emmett really wasn't able to get into because of the
time crunch. He slipped over Slides 18 and 19, but
those particular slides talk to performance standards
for applying the performance criteria.
Performance criteria are -- You know, I
think your point about the increased emphasis in the
performance based approach on those criteria is very
well taken. But there is also a lot of importance
into what standards you use to apply those criteria.
I'm not an expert in talking about this.
Emmett could explain more maybe this time or some
other time, but depending on how you apply those
performance criteria, you can get vastly different
results, vastly different levels of assurance of tube
probability -- tube burst probability.
So that's an important area of emphasis
that we've placed in some of the comments that we have
made to industry. We haven't focused on defending the
criteria, but we have focused on what are the
performance standards that you need to be assured that
those criteria are even being met.
Then the other part, I think, that Emmett
hit on quite well, although there are more details in
the slides, there are a number of comments we have
about the way the integrity assessments are being
done.
So these are all connected or
interconnected issues with the bottom line of the
performance criteria, and I think what we are trying
to say is we are looking at all of it. We will try to
be prepared next week to talk to some of the issues
you have specifically emphasized, but we think there's
a lot of importance on looking at the entire picture
of how are you actually going to do these assessments,
what standards are you going to apply to show that you
meet these criteria.
MR. BONACA: Okay. That was the question
that I asked about. Clearly, the issues are what's
the basis for the criteria, and that doesn't bother me
as much. I mean, insofar as margin, we could discuss
what margin you need, but it is margin there.
The main question is the one, how do you
measure up to the margin? What do you have to do to
demonstrate that you meet the performance criteria?
MR. SULLIVAN: Yes, I agree, and that's a
lot of what we are focusing on.
CHAIRMAN FORD: Okay. Could I ask you to
give your presentation. If you could take about half
an hour, no longer, if possible, and then you could
jump in with the relevant concerns you have.
Emmett, you had a whole lot of verbal
concerns. Maybe you could just jump in.
MR. SULLIVAN: We'll be glad to interrupt
Mohamad.
MR. BEHRAVESH: It won't be the first
time. I am Mohamad Behravesh from EPRI. I think the
nature of my presentation probably would have to be
changed a little bit based on everything that we have
heard and the questions that were raised, but I'd like
to set the stage very, very quickly for you as to what
the issues are.
In all the discussions that went on this
morning, you will find out that one topic comes up to
the surface, and that is the inspection interval. It
is not to say there aren't other issues, but that is
the one that stands out as the primary one.
So this is the inspection interval, and
within that there were two other issues kept coming up
as the prescriptive inspection, as well as the
performance based. Okay?
So I'll first put prescriptive based, and
then I'll put performance based. Have these two
things in mind. As we stand here as of now, the law
of the land still is what is in everyone's technical
specification as of now, regardless of everything that
has been said, and that says that you do a three
percent sampling of your steam generator tubes, and
you make sure that no steam generator goes more than
40 months without being looked at -- 40 months.
So as of now, this is the law of the land.
This has been the case even 20 years ago; it was also
the case. Clearly, as far back as late Seventies and
early Eighties, it was recognized that this was
clearly inadequate, clearly inadequate.
CHAIRMAN FORD: I guess my math must be
rusty. If you inspect only three percent of your
tubes, how can every tube be inspected in 40 months?
MR. BEHRAVESH: Good question. They
won't. It won't, unless --
CHAIRMAN FORD: That's what you just said.
MR. BEHRAVESH: No, no, no. I said, if
you do sampling, you do 30 percent, you are also
obligated to make sure that steam generator doesn't go
without being looked at in more than 40 months. If
you don't find degradation, you may go for a long time
and never see. And by the way, there is no
stipulation in there that says this has to be a
different three percent. You could be looking at the
same three percent.
So, yes, the question is that it is
possible that it would never get looked at all of
them. Now this was -- has been the case all along, as
early as late '79, early Eighties. And unlike the
other components like pressure vessels and piping, you
didn't have much guidance in the ASME either.
Now the ASME has lots of guidance on how
to do the rest of the inspection, how to do piping,
but has been kind of silent and inadequate on steam
generator. So that brings me to the point of what
industry started doing, recognizing that they started
developing their own set of guidelines, help, for
doing inspection.
The first one of it came out in 1981, was
revised as a formal EPRI report in '84, had benefitted
from a lot of industry support by 1988, getting
support from and input from all the NSSS, and then we
added the performance demonstration requirement,
meaning qualification of techniques and personnel and
so forth for '92, went to prescriptive sampling.
One of the reasons for going to
prescriptive sampling was that, in the absence of a
lot of information, how can you suggest something to
a large group of people that covers all the issues and
would be adequately conservative and still would keep
you within a safe margin? So that was the impetus
behind prescriptive sampling.
Then we went forward in 1997, and we put
a very strong language in terms of all the so called
guidance and recommendations which has made it into
"shalls." So these set of documents really became de
facto requirements as far as the industry was
concerned.
It wasn't -- Although the name says
guideline, in reality it is a requirement. This is
what the industry has been living with for the last
20-some years, and the point that I want to get across
to you is that everything that goes in here is
experienced based, time tested, field tested, and well
rehearsed, and result has been used from one revision
to the other revision to get us here. This is the so
called Revision 5 that the industry is currently
following now.
CHAIRMAN FORD: Is it all prescriptive?
MR. BEHRAVESH: All prescriptive. Also I
should add that, even in this revision, we have
allowed for performance based, recognizing that in
order to do performance based examination, you need to
have a lot of smarts to do performance based. You
can't just go and predict something.
You have to have a lot of data from your
past history that guides you into future to enable you
to say that I can go this length of time without
running to any problem, recognizing that to do
performance based you need a lot of information. In
practice, no one has picked this up in doing
performance based. Everyone is doing prescriptive,
because that's where their comfort zone has been.
Again, remember that the prescriptive
based, by the nature of its name, is conservative as
well in order to cover everyone.
Now the time frame is now late Nineties.
These guidelines had a provision in them that they say
that they need to be looked at in order to see whether
they need to be revised every two years or not. But
something else was happening along this time, not that
this was inadequate.
The guideline has really served the
industry quite well. What we came to recognize is
that it was beginning to be very unfair to those
utilities who had made multi-million dollar
investments in going to new materials and new designs,
and this document as it stood did not recognize that
and did not allow that.
Now again something to remember, that all
of this, regardless of what recommendations are in
here, still must operate within this. Sure, you can
exceed that. There is nothing to stop you from doing
100 percent, 20 percent inspection. This cannot be
violated even as of today. Cannot be violated.
The whole point of going to this license
change package and to these guidelines and all that is
that it is time to revise this, because this is unfair
to the new generators. So this is the whole point of
going through this revision and requesting the
revision.
Now I mentioned to you the new materials.
Surely, the new materials, they are not all the same,
but in a nutshell the revision of this guideline,
which is in the works now -- it has been in the works
for over a year now and it is up for review.
In a nutshell, it is separating these
materials, 600 mill annealed, 600 thermally treated,
and 690, and saying that 600 mill annealed should be
looked at every outage. This is no different than
what is happening right now. This is no different
than what we have in Rev 5.
It is allowing more leeway for 600
thermally treated, saying they should be looked at
every other outage at least, and for 600 thermally
treated it says every third outage.
In a nutshell, this is what is different
in Revision 6 from all the things that has been in the
past.
CHAIRMAN FORD: But that looks very
arbitrary to me. I mean, 600 TT and 690 TT have
failed at the mill. So why those multiples?
MR. BEHRAVESH; Let's go and see.
MR. BONACA: So the only change would be
the third one, I guess, 690 TT.
MR. BEHRAVESH: And 600 thermally treated,
right now.
MR. BONACA: Okay. So you went from
prescriptive to prescriptive.
MR. BEHRAVESH: Prescriptive to
prescriptive.
MR. BONACA: And the only change, really,
was for the 690 TT.
MR. BEHRAVESH: That is correct. So if
you go into a little bit more detail, things have now
-- in Revision 6 have gotten more prescriptive in that
in 600 mill annealed, 100 percent of the tubes in each
steam generator must be completely inspected in 60
effective full power months.
Remember, there is nothing of such here in
tech specs. They should be inspected at every
refueling outage, and in our -- it has been since our
Revision 4 of the guideline. To us, you don't do
sampling unless you do a minimum of 20 percent. Any
sampling less than 20 percent is not meaningful.
So the industry from long time ago has
abandoned this, and has turned this into a minimum of
20 percent. So if you do sampling, you do 20 percent,
and this is pretty much the same as we are finding in
the revision, because this material really hasn't
changed. It's the same.
Now this is where things change a little.
If you have a 600 thermally treated, and this material
is free from cracking -- if it is free from cracking,
then you can inspect 100 percent of the tubes in first
go-round in 120 effective full power months, in the
second go-round in 90, and 60, 60, 60.
The reason behind this is that these
materials have a better performance in early life than
in later life, such that your best chance of being
trouble free is at the beginning, and then we are
being conservative, dropping it to 90, for the
conservative bringing it to 60.
Again remember, this takes you into many
years in the future. This is speculation at this time
whether you would get to all of these things. These
guidelines get revised every two years.
CHAIRMAN FORD: But what's the factual
basis for choosing those numbers?
MR. BEHRAVESH: Factual basis for choosing
these numbers are that -- a series of things. There
are plants with these materials that are operating,
and they have not found cracks.
CHAIRMAN FORD: But there are plants that
are operating that have found cracks.
MR. BEHRAVESH: Where?
CHAIRMAN FORD: Byron.
MR. BEHRAVESH: That is not true. That is
not -- They haven't found cracks in the 600 thermally
treated.
CHAIRMAN FORD: Well, they haven't done a
destructive examination.
MR. BEHRAVESH: Well, yes, there may be
times -- There may be times that someone may decide
that it is more efficient or to my advantage to call
this crack and plug it and move on, as opposed to
taking it out.
CHAIRMAN FORD: My point is that you are
using very different -- Turkey Point, Byron are both
incidences where they've got 600 PTQs, but using
current NDE techniques indicates that you've got
cracking. So --
MR. BEHRAVESH: That is not our
information.
MR. HENRY: Gary Henry with EPRI. With
response to the Byron they did pull tubes, and they
were found to be benign. There was a little groove on
the OD.
With Turkey Point, I think it was Unit 4,
they found indications for which they had identified
in Unit 3 that were very similar. In Unit 4 they did
ultrasonic testing on those, which are qualified
techniques. They also found that those indications
were benign and were not present, and they have since
submitted a letter disputing or basically retracting
the fact that they found indications in Turkey 3.
CHAIRMAN FORD: Those are facts. That's
good.
MR. BONACA: I mean, if that was my plan,
I would never go ten years without looking at those.
You know, I would have to trust what you are telling
me, that there is no degradation mechanism that
happened, is true. Then what am I going to do if
there is, in fact, something new after 120 months. Do
I sue you?
All I'm trying to say is that it seems to
defy a little bit -- I understand what you are saying.
No, we haven't seen something. So you go for ten
years without looking.
MR. BEHRAVESH: But, no, there's a catch
to all of this. No, I didn't say going ten years
without looking at it. You must -- First time around
you do 100 percent in ten years. You do 100 percent
in ten years, and you must look at every steam
generator at least every other outage.
MR. BONACA: All right. All right.
MR. BEHRAVESH: Every outage. Now these
are the conditions. You must do a sample of 20
percent at each inspection. Even this 120 and 90, any
of these, require supporting degradation assessment
and operational assessment.
What does supporting degradation
assessment mean? Means that you look at yourself.
You look at your sister plants, and if anything has
happened to them, that has to come into play in your
degradation assessment. If there's an indication out
there that some other 600 thermally treated plant has
cracking, you no longer can do this.
MR. BONACA: So the 120 only refers to 100
percent of the tubes?
MR. BEHRAVESH: One hundred percent of the
tubes being crack free.
MR. BONACA: All right. Go on. You have
to inspect, but you have to do it every other year.
MR. BEHRAVESH: You inspect, and then
there's more --
MR. BONACA: You can choose how many, as
long as they make 100 percent.
MR. BEHRAVESH: Minimum 20 percent, and
then additional condition. Furthermore, we go there
and say you can't go and do all of them at the
beginning or all of them at the end. You must make
sure that you do such sampling that you are done with
about 50 percent of them by about mid-point.
This is the point of this. Examine at
least 50 percent of the tubes in each steam generator
by the refueling audit nearest to the mid-point, and
the other 50 percent by the end, which means that it
has to be spread throughout that period.
CHAIRMAN FORD: Is there some statistical
rationale for your choice of all these numbers based
on existing data?
MR. BEHRAVESH: Well, yes, there is.
CHAIRMAN FORD: Existing data will,
obviously, be mostly laboratory data.
MR. BEHRAVESH: Well, yes, there is
rationale for 20 percent sampling, where you do more
or depending on what you can expect to find. Then
these 50 percent and the length fuel cycle and this no
steam generator can operate for more than two -- If
you put these on a time scale, you would begin to see
how they fit, gives you a uniform inspection schedule
throughout.
CHAIRMAN FORD: But what you are saying,
not seeing the actual data itself and the statistical
rationale -- It presumably exists, but it has been
given to the staff so that they can do an independent
assessment of that approach? Is that correct?
MR. BEHRAVESH: Well, let me be clear as
to my understanding of your question. Rationale for
which of these things?
CHAIRMAN FORD: Well, you are giving a
whole lot of numbers there, 600 TT and, I guess we are
talking about 690. It's presumably based on some
facts and statistical interpretations.
MR. BEHRAVESH: Yes. Two answers. One is
that those numbers, those length of times are
currently supported by laboratory studies of these
type of materials, and what it takes to crack them in
the laboratory. They are supported by experience of
the current plants that are operating with these
materials.
Additionally, we are doing other surveys
of everyone else who has these materials throughout
the world to find out what their experiences are, even
doing some cases that are not like the U.S. plants.
So additional information is being
collected as we speak, although it's not available to
us today. We are trying to put additional information
together to support these numbers.
CHAIRMAN FORD: Is this the sort of things
that Roger Staehle is doing?
MR. BEHRAVESH: Probably. It could be,
could be related. Specifically, I don't think he is
addressing this, but all of his corrosion studies --
CHAIRMAN FORD: Well, he probably is.
MR. BEHRAVESH: Yes. All of his corrosion
studies would have a bearing on this.
CHAIRMAN FORD: My point is that, as we
try to resolve some of these issues -- I'm trying to
be helpful here -- all these analyses where you've
come out with these numbers and the rationale behind
them, the data has been given to the staff so they can
come up with a factual evaluation of that data?
MR. BEHRAVESH: Not all of it and, as I
understand, not to their satisfaction.
MR. BONACA: This is the prescriptive.
MR. BEHRAVESH: This is still
prescriptive.
MR. BONACA: Okay.
MR. BEHRAVESH: And then the final --
MR. RILEY: Jim Riley from NEI again. I
would just like to add a little bit more to what you
asked. These are part of the comments that Emmett has
given us on these guidelines, and we are developing
documentation to get back to Emmett on a response to
these things.
This information was here to provide a
basis, as Emmett has described. We are basically
writing a white paper to provide this additional
documentation.
MR. BEHRAVESH: But the message I want you
to get from this is that a lot of safety things are
sort of embedded in here, particularly at the end that
says, if this material at anytime is found to be
cracking anywhere, then you have to go back to the
rules for the 600 mill annealed, which means that all
of these things are okay so long as you remain crack
free and everybody else remains crack free.
The very first time that someone finds a
crack, all of this changes, and there is always the
rules for 600 mill annealed.
MR. BONACA: If it is discovered anywhere.
MR. BEHRAVESH: Yes. Now for 690 alloy,
it's pretty much like 600 thermally treated. These
periods -- The only difference is that these periods
have been extended. It's good, better, better-est.
CHAIRMAN FORD: Are there any tubes of 690
that have been in for any extended period of time?
MR. BEHRAVESH: 690? In service, about 12
calendar years in the service with about close to
eight effective full power years. There are a couple
of them running neck to neck now. There is Indian
Point, and there is DC Cook.
CHAIRMAN FORD: So exactly the same thing,
but there is presumably data of some sort to justify
those numbers?
MR. BEHRAVESH: Data to justify those
numbers, more data to be collected to satisfy NRC's
comments. Again, all of these are predicated in these
things remaining crack free with all these safeguards
built into them to make sure that, if anyone comes up
with information that says that's not the case, these
things no longer apply.
So jumping to the basis is that you -- One
raises the question, are these cycle lengths too long
or why are we going this way, what justification we
have.
This notion of collective experience is
very, very important. Although you have all these
individual utilities, individual plants that are
autonomous and operate by themselves, but once as they
keep changing these plants and have new materials,
they are all part of a big aggregate.
I mean, if you look at EdF, EdF looks at
their whole fleet of plants, and that's how they
collect their experience in terms of what is happening
to one unit and use that information in the other
units.
What is happening here is that, if even
though someone may say that, oh, you are going too
long without looking at it, in any given spring or
fall outage, although you are not looking at a 690,
someone there, someone there, someone, somebody else
is looking at 690, and based on what is written in our
guideline, it is the requirement of the guideline that
when you do your degradation assessment, you not only
look at yourself, you look at everyone else and what
has happened to them, and you take that into account.
And should you still have reason to support these long
intervals, you continue. Otherwise, you cannot
continue with those extended intervals.
CHAIRMAN FORD: Most of these phenomena
have got fairly high activation enthalpies. Is there
any temperature correction?
MR. BEHRAVESH: I am sure that they are
temperature dependent. I cannot speak to that, but
I'm sure that that has to be taken into account.
CHAIRMAN FORD: And I don't know the
physics of the PWR. Now would the PWR steam generator
change with a power upgrade? And if it did -- If it
did, and I don't know physically if it does, would
that affect your arguments?
MR. BEHRAVESH: I think some of these
differences would have to be taken into account, but
because of the fact that on the increasing guidance on
chemistry, everyone is doing the best chemistry that
they know how to, and chances of very severe outliers
that would produce an anomaly is, I think, decreasing.
If it was 20 years ago, I would be more
inclined to think that chemistries may be very
different in different places. Now temperatures --
they may be operating at different temperatures, but
chemistries -- I think everyone is availing themselves
of the best chemistry.
Now so this collective, this aggregate
experience is a very strong support for these long
cycles, knowing that something is happening here will
affect all others, and that will be taken into account
by the requirement of the guideline.
The other thing is this so called
compensatory measure which that, if cracking is
detected, all bets are off. You will revert back to
600 mill annealed, and that's understood. Besides,
there is additional assurance that secondary side
requirements also address foreign objects, and they
have to be met.
Really, furthermore, you have to realize
that this is an immense improvement over the current
requirement that we have now. I mean, this is the law
of the land as of now, and there's lots of improvement
that this program is providing.
Now there are other issues that are being
addressed. I don't want to belabor those. There are
matters of data quality ,and all of those are being
addressed.
So now I missed one point for you, going
back to these two. Going back to these two.
Everything that I said was on the prescriptive basis.
In Revision 6 we also have right of performance based.
This is the dilemma with the performance
based. People criticize prescriptive based, because
they say that it may not be -- because it's not
performance based. They encourage you to go
performance based.
You go and do performance based on the
basis of the information you have. You come up with
numbers that are huge and, all of a sudden, everybody
says, well, that can't be, I can't go for 22 years.
But that's what falls out. We have had research
project that has addressed this, and has produced
reports where there have been examples that said in a
given situation somebody could go 22 years.
Now whether that person, that utility,
will follow that, it's to be seen. But that's what
falls out of the data. What I want to get across to
you is that performance based relies very heavily on
good data. On this, you have good data from your past
history. It's hard to predict the future.
In absence of good data, I don't think
people would be too anxious to run to do performance
based. Most everyone is comfortable with doing
prescriptive.
Now NRC has had issues with performance
based, based on the numbers that it throws out. One
example that we have followed -- and some of our own
clients, the utility sponsors, have issues with that,
too. They are sort of uncomfortable with this. They
say, I see what these numbers say, but I'm not sure,
I want to go there.
So this is something that I think we will
learn more about, and until we have good data, I think
there would be reluctance on everyone's part to jump
into performance based, although this is the final --
this is a real objective and a real goal that
everyone recognizes that needs to be pursued.
So to make sure that you understand that
we have something in Revision 6. We have had the same
thing in current revision, in Revision 5, but in
absence of good data, nobody is following that.
I am going to jump to my final slide.
MR. RILEY: Mohamad, can I say one thing
here? Jim Riley again, NEI. I just want to make it
clear. I think we stated this before.
The issue on performance based is a little
academic right now, because the way that we are
approaching the regulatory controls doesn't allow for
these performance based methodologies unless the NRC
gives their approval of an interval determining
methodology.
So what we are really talking about from
the purposes of regulatory controls now is directed at
prescriptive, not performance based. Like Mohamad
says, we want to get there, but we know there is more
work that has to be done before we are there.
MR. BEHRAVESH: This is my last slide.
The latest draft is currently in review by the
industry. In the previous draft that we sent out a
few months ago, we had several hundred comments,
including those from NRC. Those have been addressed.
We have gone out with a new draft. We expect
responses by mid-December. We will start addressing
those comments by mid-January.
The important point again to emphasize is
that consensus will be achieved. We have 20 years of
history doing these guidelines, and we have had more
contentious issues among the industry themselves to
come to a consensus, and that has happened. So
consensus will be achieved as for the past revision,
and we have a goal of putting this document out by
mid-year.
CHAIRMAN FORD: Thank you very much
indeed. We've got 25 minutes left. Could I ask -- Ed
is going to ask us for advice for next week. Does
anyone have any comments before we give specific
advice?
MR. BONACA: Well, I think that this
presentation gave me a real feeling for what is being
on the table, and it shed a lot of light on the
previous presentations, which were very good. But I
think they were more general. So we are left with
some questions regarding the specifics.
So if I had to choose an order in which I
would bring the presentations, it would be maybe NEI,
but this information, I think, is better to help us.
CHAIRMAN FORD: Bear in mind that the
members have not heard anything about this since April
1999. Do you think that there should be an opening
segment to bring them up to date as to what the
objective of this was, plus the overall problems?
MR. KRESS: Yes, but very short.
CHAIRMAN FORD: Very short, but also
there's regulatory concerns as well as technical
concerns. I think we agreed early on, without us
hearing about the details, that there are no
regulatory concerns currently on the table. Is that
correct? That's not correct?
MR. SULLIVAN: No. I think that is what
we said. I think what we said was that -- We didn't
belabor this, but we had some exchange over recent
months of the regulatory controls issue. We've
settled that as of yesterday.
CHAIRMAN FORD: Bear in mind, at the end
of the day you are requesting that we write a letter
-- ACRS writes a letter essentially saying, hey,
you're going in the right direction, guys. It's
another ten years before we hear about this particular
topic, and that the technical issues that you have
honed in on are the correct ones to be resolved by the
time your write your SR and safety evaluation report.
That's what your expectations are. I
guess I'm asking the subcommittee here for advice to
them as to what they should be hitting.
MR. BONACA: When I looked at their
presentation, I see a lot of reasonable steps. I
think it's a responsible program. I'm sure that there
are plenty of issues that you have to hammer out, but
I think that you are going in the right directions,
has improvements definitely over the current problem.
It takes into consideration certain assumptions
regarding improved materials.
On the other hand, it takes into account
the possibility that cracks are being identified and,
therefore, steps back the program. I think it's a
very responsible approach, and I think once we see
that, then the concerns of the NRC come more in
perspective.
I mean, they are looking more at the
details, the specifics, and so if you go into those,
I think that they will be more clear for the
committee. I would have a brief introduction
definitely in the beginning to put the whole thing in
perspective, but I think it's important that in a
couple of years -- Again, I view the program as
responsible.
MR. KRESS: I would like to hear more
about that the issues on Slide 18 and 19 strike me as
fairly important ones. That is one of the things that
disappeared from the integrity guidelines. There was
a probabilistic statement in the earlier guideline
that seems to have vanished.
I mean, you not only had to demonstrate
the factor of three and 1.4, you had to demonstrate a
probability of cracking also. There were two
requirements, as I recall, in the earlier version. Is
that an option?
MR. MURPHY: The guidelines address a
situation where you are taking a statistical approach
to assessing where you are relative to the 3 delta P
criteria, for example. And it states that each tube
should have a relatively high probability of meeting
the 3 delta P criterion.
In addition, there's a criterion that
basically states that there should be a relatively
high probability that the population of tubes will be
capable of meeting the 3 delta P criterion.
The major failing of the guideline is that
that second criterion is not consistently carried
through the tube integrity assessment guidelines or
the other guidelines either. What that means is that
where you are dealing with degradation mechanisms
where there's a sizable number of flaws, which is
often the case, you may well have a number of tubes
which each individually has a high likelihood of
satisfying the criteria, but when you look at the
population, there's actually a relatively low
likelihood that you are going to have all tube
satisfying the criteria.
So that clearly is a pretty fundamental
issue I think that the guidelines need to do a better
job of addressing.
MR. KRESS: I guess my comment was in the
draft Reg guide -- and I thought in the first version
of NEI 97-06 -- that requirement was actually a high
level requirement. It wasn't down in the guideline.
It was given equal weight, in fact, with 3 and 1.4, or
am I wrong?
MR. BEHRAVESH: I think you are confusing
the probabilistic criteria with the deterministic one.
MR. MERILO: I'm Mati Merilo from EPRI.
I think we are talking about two separate
requirements. We originally had a probabilistic
requirement which the NRC said that they didn't really
like, because they weren't able to tie that back to
the deterministic criteria.
So we do have it in the guidelines, but
said you require NRC approval before you can use that.
MR. KRESS: I see. So you didn't have to
satisfy both then?
MR. MURPHY: Well, I think we are talking
-- A lot of us are talking past each other at this
point. I think Mati was referring to a probabilistic
criteria that applied to probability of failure during
main steam line break, as opposed to the likelihood or
the probability that you are going to satisfy a 3
delta P criteria or the 1.4.
MR. KRESS: Okay, I see. I understand
now.
MR. MURPHY: Yes. We have entertained in
the context of the ODSCC arc the notion that there
should be an acceptance criteria with respect to the
probability of burying a tube under steam line break
conditions where no credit is taken for the presence
of the support plate. But in general, we haven't
agreed to such a criterion in any other application.
Rather, we are looking for a high degree
of assurance that you are meeting 3 Delta P or, you
know, the 1.4.
MR. BONACA: By the way, this is a very
important issue, too, and we need to talk about it.
But it is interesting how two presentations really are
going by each other. I mean, what we heard from EPRI
today was about the prescriptive approach. We didn't
hear anything about the performance based.
The main issue we had when you had your
presentation was on the performance based. So you
know, we need to hear from EPRI of when you are coming
out with the revision. You said that you already have
a revision in place with some performance based
criteria.
MR. BEHRAVESH: Really, no criteria in any
form of detail. It's a hint of things to come. It's
saying that, yes, there is another avenue to pursue,
but in absence of data, in absence of well tested
methodology, really we can't say anything more. It's
mostly expressed as a goal to achieve as opposed to a
path to follow.
MR. BONACA: I got kind of thinking,
because I thought that we would see in front of us
soon enough an approach that is performance based. So
I was kind of alarmed, and I wanted to know what's the
basis for this. But from what I hear now, it's not an
imminent bet.
MR. SULLIVAN: I don't think it is
imminent, but I think our presentation -- It's always
really difficult to figure out what is the best way to
present this material. There's a lot of it.
I think our presentation grew out of the
perspective that as recently as the beginning of this
year, we have been heading in the direction of a
performance based approach. We've gone down a
different avenue, at least for the more near term.
I think we agreed with NEI and the
industry that that's a success path for the near term
for getting into place a new regulatory framework, but
all of these issues are still going to be there when
we devote our attention to the performance based
approach.
So it kind of came out of a historical
perspective that we wanted to let you know that we
have a number of issues. We have identified them to
industry, and then we have taken another avenue to
getting the regulatory framework on board.
MR. BONACA: I would just say, that was
more reflecting on the shorter time we have next week
and we got -- I was sidetracked somewhat, and I think
we want to prevent that from happening in the meeting.
MR. SULLIVAN: So you are recommending
that next week we basically try to focus on the
direction we are going in and not try to present
information on both avenues, which may turn out to be
confusing.
MR. BONACA: I would just focus on the
most imminent approach.
MR. SULLIVAN: The inspection interval
approach?
MR. BONACA: Right.
CHAIRMAN FORD: Tom, do you have anything?
MR. KRESS: Yes, I agree with what he
said. I would like to see more data based.
CHAIRMAN FORD: I think what you are
hearing is that we've got one and a half hours. The
traditional one is 45 minutes, therefore. Out of that
45 minutes, I would suggest that, contrary to what you
are saying -- we can re-debate this, Mario -- that you
give a very short background on the regulatory
situation, how we want to go toward ultimately
performance based criteria --
MR. SULLIVAN: But don't belabor it.
CHAIRMAN FORD: -- the whole background to
the 97-06, and then now Rev 1 and the Generic Change
Package, just a very -- two minutes, five minutes,
short.
MR. SHACK: No, I think it's important to
get in what the regulatory requirements that you now
currently plan to impose are. I'm not worried about
historically you thought you were going to have to do
without this, but the notion -- Mohamad stated that,
if they do go to a performance based approach, you are
going to have to approve the methodology for doing
that.
I think that is an important regulatory
statement, and the slide that sort of got buried in
Emmett's thing, that if they are going to change these
maximum intervals, that's again something you have to
do.
I wouldn't be too concerned about, again,
you know, historically you were heading one way, and
now you have changed directions. Just tell us what
the current plan is.
MR. BONACA: I think, if you do that, at
least we don't get hung up pursuing just how do you
justify these criteria and how do you measure up to
those, because that could take the whole Committee in
that direction.
CHAIRMAN FORD: And I also advise that,
bearing in mind the Committee is being submerged in
all these DPO issues in the last year, that it would
be worthwhile -- it would behoove you to at least
mention Jim's comment, that the EPRI guidelines are
living documents, and they will take into account
lessons learned from the DPO action plan, etcetera.
Everything I've said is literally within
ten minutes to start. The rest of the time, I think,
should be focused on the technical issues, what has --
I guess one slide, everything that's being taken into
account that has been addressed.
I think you should be prepared -- and
result. You should be prepared to back up the
statements about the 1.4 and the 3 safety factors with
some data. There's a performance issue that Bill just
brought up on your Slides 18 and 19. I think those
are important. But the majority of time should be
spent on the inspection to those and, if I could
suggest, that maybe you start off with your viewpoint.
Then you end up with -- and Emmett had some good
slides, word slides.
In all of these, I really urge, use data,
please, to make your points.
MR. KRESS: With respect to Slide 18, that
was very interesting how they would do the analysis to
provide those assurance, the 90 percent assurance.
CHAIRMAN FORD: Yes.
MR. KRESS: I don't -- I have to sit down
and try to figure out how I would do this. It's not
easy.
CHAIRMAN FORD: Bear in mind, your
expectation is that we will write a letter saying that
you have covered all the technical issues, and those
are the appropriate outstanding ones. That's what you
want us to do, and so we need the information to write
that.
It would also be interesting to finish up
with Emmett's time things of work: When is this all
going to all finish, i.e., completely finished by
December 31st of next year.
MR. SULLIVAN; One thing that we didn't
get into, I think because we were wanting to focus
across the board on all of the issues, were the
specific questions and so forth that we have raised on
the proposed inspection intervals.
Now that came out in the course of
Mohamad's presentation. I think somebody offered
that. I don't know whether it was Jim or Emmett, but
we have a number of questions that are similar to the
ones that you were raising.
I guess what I'm hearing you say is we
should probably steer toward those issues that we have
raised and that are being worked on, rather than the
ones that have to do with the performance based
approach.
CHAIRMAN FORD: I've got another question
to my colleagues here. It's not my area of expertise.
Bill, you brought up the question of severe accident.
I know Dana is also worried about iodine, etcetera.
Is this an issue that should be even brought up here
or not? Is it going to be asked? Should they be
fore-armed?
MR. KRESS: I suspect that the issues will
take the form of these new inspection intervals plus
the associated increase in risk. Steve addressed that
to some extent. I don't think the iodine spiking
issue is likely to come up.
CHAIRMAN FORD: Okay. Let that be
forewarned, fore-armed. Any other comments? Well, I
hope you found it useful rather than destructive. We
did give you a hard time, Emmett. I apologize.
Are there any other comments, questions?
MR. SULLIVAN: I guess I have a question.
Maybe it's for the other side. But I think what I
hear you recommending is that you would -- from the
second presentation coming from NEI, or industry, you
would like the details that Mohamad presented more
than the background that Jim presented. Is that what
you were saying?
CHAIRMAN FORD: On that aspect, that
helped me personally, because I'm new to this game.
But to the rest of the guys, they know this left,
right and center, I suspect.
I think you that you all should start out
with the regulatory background and the technical
issues that you have examined relative to the Generic
Change Package and NEI 97-06.
Just state that you are prepared to defend
all those that you agree with that are no longer
issues, and let Mohamad take the majority of the
technical discussion, I think, on inspection, because
that is, as I hear it, the main thing on the table.
Then you finish off and respond to make
your rebuttals or your concerns which you put down in
words, because I do urge everybody to come along with
data to back up the statements.
Okay.
(Whereupon, the foregoing matter went off
the record at 11:54 a.m.)
Page Last Reviewed/Updated Tuesday, August 16, 2016
Page Last Reviewed/Updated Tuesday, August 16, 2016